Special Section : Environmental Biotechnology

 

Effect of Fe2+ Concentration on Microbial Removal of Ni and V from Spent Catalyst

Gómez-Ramírez Marlenne; Yulia Alejandra Flores Martínez; Leticia Jazmín López Hernández; Rojas-Avelizapa Norma G

  • Abstract

    The oil industry use huge quantities of metal catalysts in order to produce desirable products from the raw material. Once these catalysts are exhausted, they are discharged to environment representing a serious environmental concern due to their high content in metals such as Ni, V, Co, Mo, Fe among others. Different efforts have been done to minimize the negative impact of spent catalysts. Biotechnological approaches appear to be a good alternative since microorganisms have different mechanisms to survive, growth and remove metals at these severe conditions; however, different parameters need to be optimized to reach an effective treatment. As a first approach, and due to the effect of iron on microbial metal leaching and the iron content in the spent catalysts; the present study reports the effect of two different Fe+2 concentrations (2 g/L and 32 g/L) on the ability of seven isolates to remove Ni and V contained in a spent catalyst in 125 mL Erlenmeyer flasks containing 9k liquid medium at 30°C, 150 rpm for 7 days. Results indicated that isolates coded as MNSH1-PHGII-1 and MV-9K-4 showed the maximum Ni and V removal from spent catalyst at a Fe2+ concentration of 2 g/L, which corresponded to 193 and 373 mg/Kg for Ni and 560 to 1038 mg/Kg for V, respectively. Nickel removal was improved 4 - 4.5 times and V, 2.4 and 7.7 times by the isolates above mentioned, in comparison when Fe2+ was used at 32 g/L. According with data, isolates MNSH1-PHGII-1 and MV-9K-4 could be excellent candidates for biotechnological approaches to leach metals; however, more studies are need to optimize metal recovery.

 

Removal of Lead from Aqueous Solutions By Brewer´s Spent Grain

Hilda Isabel Salazar González, Verónica Almaguer Cantú, Guadalupe Rojas Verde, Lilia H. Morales Ramos, Carlos Solís Rojas, Katiushka Arévalo Niño

  • Abstract

    The potential utilization of Brewer’s Spent Grain (BSG) was investigated in the removal of Lead from aqueous system. Batch sorption process assessment of the effects of process variables showed that pH, initial metal ion concentration and dosage amount affect the sorption and uptake of Lead ions by BSG. Analysis of the sorption process showed that second-order kinetic model gave good description of the process for Pb, R2 = 0.999. Kinetic studies showed that equilibrium was reached within 30 min. Equilibrium isotherm analysis of the sorption process data showed that the Langmuir isotherm fitted very well for lead sorption by BSG. The highest measured uptake was 28.57 mg g-1 at 0.33 g mg−1 min−1. The results of the studies indicate that the metal ion was favorably adsorbed onto the adsorbent with a removal efficiency of 95.45%. This study suggests that biosorption by spent grain can be an effective way of metal ion treatment and can be consider another way to use the byproducts from the brewing industry .

 

Enzymatic and Expression Profiling of Oxidases Produced by Pleurotus ostreatus in Submerged Fermentation in the Presence of Remazol Brilliant Blue R (RBBR) and Yellow Azo (AYG) Dyes

Martha Bibbins-Martínez, Cristhian Pérez-Parada, Soley Nava-Galicia, Analilia Arroyo-Becerra, Miguel Ángel Villalobos-López, Rubén Díaz-Godínez, Gerardo Díaz-Godínez

  • Abstract

    The white-rot fungus Pleurotus ostreatus produces laccase (LAC), manganese peroxidase (MnP) and versatile peroxidase (VP) within other oxidases. We studied the effect of the textile dyes Remazol Brilliant Blue R (RBBR) and Yellow Azo (AYG) on enzyme activity and expression profile of the peroxidases produced by Pleurotus ostreatus during its growth in submerged fermentation.In general terms enzymatic activity increased in the presence of both textile dyes that compared to the basal condition being higher for laccase and MnP in RBBR and for VP in AYG fermentation. On the other hand, the gene expression fluctuated in each condition and growth time tested. The laccase isoform poxa1b gene seems to be the highest constitutively expressed. The induction effect of dyes on gene expression was clearly observed for the vp gene in the presence of RBBR with almost 300 fold level. For the laccase isoforms, the gene showing the highest upregulation was pox4 with inductions levels ranging from 800 and 25 folds in AYG and RBBR respectively.The enzyme activity and expression profile analysis obtained suggest the coordinate participation of the enzymes under study in the oxidation and probably mineralization of the dyes evaluated. Moreover, the above results show that both dyes act as inducers of the enzyme activity and modify the gene expression profile of the oxidases under study. This effect may be the result of differences in chemical structure and physicochemical properties of these compounds On the other hand the induction levels observed for mnp gene ranged from 5 to 20 folds in AYG and RBBR  espectively.  The enzyme activity and expression profile analysis obtained suggest the coordinate particaipation of the enzymes under study in the oxidation and probably mineralization of the dyes evaluated. Moreover, the above results show that both dyes act as inducers of the enzyme activity

 

Extraction and NMR Determination of PHB from Azospirillum brasilense Sp7

María Eugenia Patiño Iglesias, Lucía Soto Urzúa, María Laura Orea Flores,Delia López Velázquez and Luis Javier Martínez Morales

  • Abstract

    Microbial polyhydroxyalkanoates (PHAs) are a family of natural polyesters structurally diverse produced by many bacteria trough fermentation. They are accumulated intracellularly as energy storage compounds and they can be produced from renewable resources. PHAs have been attracting considerable attention as biodegradable substitutes for conventional polymers and these have gained major importance due to their structural diversity and close analogy to plastics. Bacillus megaterium, Alcaligenes eutrophus and others bacteria are known to produce a biodegradable homopolymer, poly(3- ydroxybutyrate) (PHB). Azospirillum brasilense has not been widely studied for PHB production. This paper describes its isolation from Azospirillum brasilense Sp7. Also, its spectroscopic characterization by Nuclear Magnetic Resonance spectra (NMR) of protons 1H  nd carbon 13C. These techniques confirmed its purity. In the same way, its infrared spectrum (FTIR) allowed to corroborate the absence of another compound different to the PHB and also calculate de Crystallinity Index. From this work, it may be concluded that Azospirillum brasilense Sp7 is a suitable microorganism for bioproduction of the PHB. 

 

Extracellular Polysaccharides and Biomass Production in Cyanobacteria Isolated from Stone Monuments in Dry Zones of Mexico

Juan Vázquez-Martínez, Enrique Ramírez-Chávez, Juan Manuel Gutierrez-Villagomez,Jorge Molina-Torres.

  • Abstract

    Microorganisms develop in the form of cellular clusters known as biofilms. Biofilm’s microbial cells are embedded in a matrix of extracellular polymeric substances (EPS). Cyanobacteria are photosynthetic prokaryotes that produce considerable amounts of EPS. This characteristic allows cyanobacteria to develop on aerial mineral surfaces, exposed to the atmosphere under low humidity conditions. Cyanobacteria biofilms can grow on rock-monuments surface affecting the stability of this type of Cultural Heritage. In this work we studied production and composition of EPS in relation to cell growth. At the first stage, a biofilm-forming cyanobacterium was isolated from rock-monument surface. Growth and EPS production kinetics were assessed during 42 days. Polysaccharide composition was determined by GC-EIMS. The stationary phase occurred between day 28 and day 42, the biomass concentration during this phase was 1.28 g/L of culture medium. During the stationary phase the EPS production was the 10% of the dry weight of culture. The 30% of these polymers are polysaccharides mainly composed by D-galactose, D-mannose, and D-glucose. The production peaks of released exopolysaccharides were at days 15 and 42. The production peak of cell envelope exopolysaccharides was at day 28. It was observed that growth is not proportional to the EPS production (RESP and CEPS), therefore the EPS production could be dependent on cell density.

 

Discoloration of Indigo Carmine Using Vegetal Extracts

Myrna Solís, Aida Solís, Herminia . Pérez, Norberto Manjarrez, José Luis Gil, Héctor S. Luna

  • Abstract

    Peroxidases are used to degrade different compounds such as textile dye. We tested the ability of different extracts, including chayote, cucumber peel and fruit, spring onion stalk and fruit, and leek fruit, to discolor indigo carmine (IC). The extracts at different pHs were analyzed for peroxidase activity using the maximum for discoloration of IC. Vegetables were found to have the highest peroxidase activity at pH between 5 and 7. All extracts had the ability to discolor IC in different percentages. IC at 50 ppm was easily and completely discolored by all extracts, whereas onion fruit, onion stalk, and leek fruit extracts could discolor the IC solution at 100 and 200 ppm. Onion fruit extract could decolorize IC completely at 500 and 1000 ppm. Results are interesting because represent an alternative to reuse residues and resolve a contamination problem like discoloration of textile effluents.

 

Influence of Yellow Azo Dye on the Expression Profile of Phenoloxidases of Pleurotus ostreatus Grown in Submerged Fermentation

Rubén Díaz, Berenice Nava-Galicia, Gerardo Díaz-Godínez, Martha Dolores Bibbins-Martínez.

  • Abstract

    Pleurotus ostreatus is a white rot fungus capable of degrading many xenobiotic and recalcitrant compounds due to their ability to produce a nonspecific enzyme system able to catalyze the oxidation of many types of organic compounds including textile dyes. Several studies had demonstrated the influence of the structure of dyes on the patterns of expression of phenoloxidases, produced by this fungus during the process of growth and dye oxidation. The objective of this research was to study by RT-PCR the temporal expression of five phenoloxidases genes (1 Po-DyP, 4 Po-DyP, 2 Po-MnP, 3 Po-MnP y 4 Po-MnP) of Pleurotus ostreatus grown in submerged fermentation in the presence of yellow azo dye (4-amino-1,1 '-azobenzene 3,4'-disulfonic acid mono-sodium salt). This dye induced the expression of phenoloxidases genes however, the expression level fluctuated in each monitored growth phase. The highest induction was observed for 4 Po-DyP and 4 Po-MnP. Patterns generated for each peroxidase gene, suggest that the 4 Po-DyP in conjunction with 4 Po-MnP genes contribute to the decolourization of the dyes. Furthermore enzymatic and molecular studies of dye peroxidase produced by Pleurotus ostreatus could contribute to have enzyme selection criteria leading to the development of effective bioremediation methods.

 

Anaerobic digestion in two stages of primary and secondarysludge anaerobic reactors with flow up

Jesús Terreros-Mecalco, Oscar Monroy-Hermosillo, Adalberto Noyola-Robles,Florina Ramirez-Vives and Alejandro Olmos-Dichara

  • Abstract

    A train sludge treatment based on a new configuration and design of tubular glass UASB reactors upflow jacket, drawing 10 L volume and working volume of 8.6 L of mixtures of primary sludge (PS) were studied and secondary sludge (SS) in two stages. The first hydrolysis-acidogenesis in a mesophilic reactor (35±3oC) without controlling pH, agitation, recirculation or pre concentrated sludge. The results showed that the reactor served as the settler-reactor, coming to have concentrations of 15 to 56 g TSS/L promoting solids retention time (SRT) 11 to 34 d. A first order kinetics in the destruction of solid, a value of the hydrolysis constant (k) of 0.0681d-1 at a hydraulic retention time (HRT) of 1 d, 12.5 d SRT, organic load (Bv) of 14.2 kg VSS/m3.d by 29 % and methane production rate of 0.009LCH4/LR .d. In a second thermophilic stage (methanogenic hase) to 55±1oC, also acted as the reactor-settler reactor and observed a correlation between the solids concentration of the reactor, the HRT, the SRT of the destruction of solid, and organic load supplied with suspensions given 1.8 to 9.4 g TSS/L in the feed concentrations of 6.5 was reached 32.8 g TSS/L have SRT allowing 7 to 22.9 d. And there is the further destruction of solids with SRT 7.4 d to 66% at organic loads (Bv) of 3.5 kgVSS/m3.d of 55% to 7.2 kgVSS/m3.d, SRT of 15.2 d with QCH4 speeds of 0.005 and 0.09 LCH4/LR.d. However, the value of k4 confirmed its slowness in converting CH4 VFA. 

 

Removal of Indigo from Textile Wastewater by Bioadsorption with Vegetable Waste Material

Pérez Ismael, Solís Aída, Pérez Herminia, Manjarrez Norberto, Gil José Luis, Solís Myrna, Cassani Julia

  • Abstract

    Textile industry is one of the most polluting industries in the world. An adsorbent is of low cost if it requires little processing, is provided in nature or is a by-product of waste material. The objective of this work was to explore the feasibility of water hyacinth and pineapple crown as low cost natural adsorbents, to remove the indigo present in the wastewater from a textile laundry. Biological materials were dried at 80°C 48h, the dry material was grinded until fine powder; 30, 60, 100, 130 or 160 mg of the powder were mixed with 3 mL of textile wastewater contaminated with indigo. The removal of indigo was determined by measuring the absorbance of the supernatant at 610 nm. The removal of the indigo present in 3 mL of textile wastewater was between 63 and 68% using 100, 130 and 160 mg of water hyacinth powder, whereas in the case of pineapple crown the adsorption was between 68 and 70% using 130 and 160 mg of the powder. The waste materials tested are an attractive and viable alternative for the treaatment of textile wastewater, in such a way that the material acquires an aggregated value.

 

Biosorption of Hexavalent Chromium Using Inactive Biomass of Aspergillus sp.

Juan Andrade-Rivera, Luis J. Galán-Wong, Katiushka Arévalo-Niño, Guadalupe Rojas-Verde, Verónica Almaguer-Cantú

  • Abstract

    In this study Aspergillus sp. cells were cultivated using nutrient broth media at room temperature and 150 rpm. The media was inoculated with about 2 x 106 conidies/mL. Cultivation period was about 7 days. After cultivation, cells were harvested by centrifugation (4000rpm/15 min) and then dried in oven at 60°C for 48 h. Stock solutions (1000 ppm) of Cr6+ was prepared by dissolving analytical grade of K2CrO4, in distilled water.The effect of pH on adsorption was studied and found that the results at pH 6 the removal percentage of Cr6+ was small. The removal percentage increased rapidly with decreasing pH, and reached a plateau around 90% at pH 2. The results showed strong pH dependence of biosorption. 

 

Growth of Pleurotus ostreatus ATCC 3526 in different concentrations of di (2-ethylhexyl) phthalate in submerged fermentation

Córdoba-Sosa Gabriela, Torres José Luis, Ahuactzin-Pérez Miriam, Díaz-Godínez Gerardo, Díaz Rubén, Sánchez Carmen

  • Abstract

    (Di (2-ethylhexyl) phthalate (DEHP) is a plasticizer used in the manufacture of plastics which impart flexibility to polyvinyl chloride resins. This is an endocrine disrupting compound that could lead to cancer. It has been reported that Pleurotus ostreatus is a fungus capable of growing using DEHP as energy source. Specific growth rate (μ), maximum biomass (Xmax), laccase and esterase activities, pH profiles and enzymatic kinetic parameters were evaluated in Pleurotus ostreatus grown in DEHP in submerged fermentation. Flasks of 125 ml containing 0, 750, 1200 and 1500 mg of DEHP/l were used. All media were added with 10 g of glucose/l. Flasks containing 50 ml culture medium were inoculated and incubated at 25 0C for 16 days on a rotary shaker (120 rpm). Xmax and μ were evaluated using the logistic equation. Biomass (X) was determined by dry weight method. Laccase and esterase activities were evaluated using 2, 6-dimethoxyphenol and p-nitrophenyl butyrate as substrates, respectively. Enzymatic kinetic parameters were evaluated based on maximal enzymatic activity (Emax). Results showed that the highest Xmax was observed in media containing 1500 mg of DEHP/l and the esterase activity was much higher than the laccase activity at the beginning of the stationary phase in medium containing 1500 mg of DEHP/l. These results suggest that there was no catabolite repression (glucose effect) and that DEHP was used as carbon and energy source by this fungus.

 

Green Synthesis of Gold Nanoparticles Using Latex of Jacaratia Mexicana

Juan Manuel C Figueroa, Ada M. Ríos Cortez, A. Orduña Díaz, O. Zaca Moran, A.Martínez Ayala, R. Delgado Macuil, Valentín López Gayou

  • Abstract

    In recent years, green synthesis of gold nanoparticles (AuNPs) has gained much interest because of its importance in medicine and industry, harnessing the endemic flora of each region favors the reduction of costs for this synthesis method that uses biological material from plants as a reducing agent and stabilizer. In this work we report a method for biosynthesis of AuNPs using latex obtained from the fruit of Jacaratia mexicana, which is an endemic plant of Mexico. Gold nanoparticles were obtained from the reduction process of aqueous gold ions exposed to latex of Jacaratia Mexicana. Gold nanoparticles were characterized by UV–vis spectroscopy and shown distinct peak ranged from 545 to 560nm depending on the concentrations of the latex and gold ions.

 

A UV Tolerant Wild-Type Strain Of Bacillus Thuringiensis With Antagonistic Effect Producing Melanin

Francisco Salazar, Aurelio Ortiz, Estibaliz Sansinenea

  • Abstract

    Bacillus thuringiensis (Bt) is a Gram-positive, spore-forming, soil bacterium and the most successful biological control agent used in agriculture, forestry and mosquito control. However, one of the main disadvantages is that the insecticidal activity of Bt formulation, is little stable and rapidly lose their biological activity under field conditions, due to the ultraviolet radiation in sunlight. Melanin is known to absorb radiation; therefore photoprotection of Bt based on melanin has been studied. Several research groups have obtained Bt mutants producing melanin by successive rounds of UV radiation or by after treatment with the mutagenic agent. However, these mutants lost their toxin-encoding genes. Bacillus thuringiensis strains were isolated from soils of different States of Mexico and pigment extraction was followed. Pigment was characterized by some chemical tests and by IR spectrum. UV (Ultraviolet) irradiation experiment was realized to probe the melanin efficacy. ELI52 wild type strain of Bt was confirmed that naturally produces melanin. The Cry protein analysis suggests that ELI52 is probably a B. thuringiensis subsp. israelensis strain with toxic activity against diptera order of insects. The characteristics and UV protection efficacy of melanin on Bt formulations was probed after UV radiation, comparing the results with melanin non-producing strain. L-DOPA was also detected in the culture. This strain showed an antagonistic effect over some common bacteria of the environment. As conclusion, we can report that ELI52 is a good bioinsecticide, which produces melanin constitutively, so this strain can be UV tolerant with its insecticidal capacity unaffected, and that can inhibit the growth of other environment bacteria.

 

Determination Of The Antimicrobial Activity In Extracts Of Bacillus Thuringiensis Isolated From Soil

Melanie Ramirez, Jessica Vaca1, Aurelio Ortiz, Estibaliz Sansinenea

  • Abstract

    Bacillus species produce secondary metabolites that are the object of natural product chemistry studies. Among Bacillus species, many isolates of B. thuringiensis (Bt) also produce an assortment of various natural compounds that are secreted into the culture medium with broad biological activities, such as antimicrobial, antiviral and antitumor activities, that enable the bacterium to survive in its natural environment other virulence factors. The objective of this study was to evaluate the potential of different Bt strains isolated from soils in order to produce biologically active substances like antibacterials. Bacillus sp strains were collected from soils of different locations of Mexico. Their protein content was analyzed by SDS-PAGE distinguishing Bt from B. cereus. A screening of the isolates was realized extracting the secondary metabolites using amberlite resin of several strains. The extractions were realized in TSA culture media, due to it was the best for secondary metabolites production. The antimicrobial activity of the extracts of secondary bacterial metabolites was evaluated using disk diffusion tests against diverse bacteria such as, Micrococcus luteus, Staphylococcus aureus, Serratia marcescens, Klebsiella pneumonia, Escherichia coli Pseudomonas aeruginosa, Staphylococcus saprophyticus, Streptococcus agalactiae, Salmonella sp, Bacillus cereus, Vibrio cholerae, Vibrio parahaemolyticus and Shigella sp using common antibiotics as positive controls. We have some extracts of Bt, with strong inhibitory activity against many of the bacteria before mentioned which have clinical importance and have developed resistance to many class of antibiotic that are in use. We are purifying and characterizing chemically the compounds responsible for this antibacterial activity.

 

Remediation of a Soil Contaminated with Fat from Wastewater of a Cheese Industry

M. Guadalupe Vicencio-de la Rosa, M. Elena Pérez-López , M. Adriana Martínez-Prado and M. Engracia Velasquez-Saucedo

  • Abstract

    Research was conducted to implement a composting process to remediate soil contaminated with fat from cheese factory wastewater. Four composting treatments (9 kg) were established, where nutrient content was varied and/or soil structure by adding fertilizer and/or oat straw as follows: T-I = contaminated soil (control); T-II = contaminated soil + fertilizer; T-III = contaminated soil + oat straw; and T-IV = contaminated soil + oat straw + fertilizer. Soil moisture in experimental units was maintained to 75% of field capacity, mixtures were aerated once a week, and measurements of pH, electrical conductivity (EC), fats, and microorganisms were performed every 4 weeks. T-IV was the most efficient with 96% removal of fat followed by T-II and T-III with 86% in both cases, and 81% for T-I. In T-IV, increase of nutrients and soil porosity improved microorganisms working conditions so there was a greater fat removal. Bacteria and fungi grew normally in soil with a pH of 8.2 and EC of 10 dS m-1. The cost (Mexican pesos) of remediation of 222 tons of soil was: $8,130 (T-I), $34,000 (T-II), $24,810 (T-III) and $50,685 (T-IV). It is worth mentioning that soil is impacted with salt content in wastewater, increasing restoration cost.

 

Biogas Production from Mixtures of Manure and Other Residues in Batch Reactors

M. Guadalupe Vicencio-de la Rosa, Roberto Valencia-Vazquez, M. Adriana Martínez-Prado and M. Guadalupe Reyes-López

  • Abstract

    In this research biogas production of anaerobic digesters was evaluated at laboratory scale (1 L), batch reactors were operated with mixtures of livestock manure and diverse residues; where rumen was included. Mixtures of residues were adjusted to a 20% of total solids content with an 80:20 ratio ; manure-milk fat, manure-oat straw, manure-oat residue, food residues-manure and rumen-oat residue. The volume of gas was measured by the displacement method and the biogas composition was determined with a portable biogas analyzer. The processes lasted 70 days and were conducted by triplicate. The differences among mixtures in production and quality of the biogas were determined by an ANOVA and Neuman-Keuls means test with α = 0.05. Biogas production in reactors with manure (1.3 to 2.4 L) did not show any statistical significant differences during the observation period, as well as in methane production (0.85 to 1.3 L). However, the rumen mixture had the highest methane content (1.7 L), whereas the mixture of food residues and manure produced only 0.074 L of biogas. It is suggested to reduce by half the solids content and include rumen as inoculum to increase quantity and speed of biogas production.

 

Application Of Spent Mushroom Substrate Of A. Bisporus For The Bioremediation Of Soils Contaminated With Hydrocarbons

Amparo Mauricio-Gutiérrez, Ana Lilia González-Sorcia, Teresita Jiménez-Salgado, Lucía López-Reyes, Armando Tapia-Hernández

  • Abstract

    Agricultural soils from Acatzingo, Puebla, Mexico have been impacted by oil spills; therefore it is necessary to recover. The spent mushroom substrate (SMS) of Agaricus bisporus has been reused on the bioremediation. This research aimed to determine the diesel´s biodegradation in agricultural soil using SMS. Soil and SMS were characterized physicochemically and microbiologically. Microcosm experiments were carried with different doses of non-sterile SMS (5, 10, 15 and 20%) and sterile soil contaminated (7039 ppm diesel) incubated at 25 and 37oC for 28 d; CO2 production, diesel´s biodegradation, and initial and final population cultivable of bacteria and fungi tolerant at diesel were determined. Soil contained 2.04% organic material, 0.032% total nitrogen and 0.00256% phosphorus; and SMS presented 57.6%, 1.46% and 0.79% respectively. The soil had generally a higher number of cultivable microbial populations (6.02, 5.04, 4.04 and 2.90 Log cfu/gss bacteria, diesel-tolerant bacteria, fungi, and actinomycetes respectively). In microcosm experiments treatments incubated at 37oC showed higher biodegradation and CO2 production. With 15% of SMS the highest biodegradation was obtained (68.75 %). Fungi population showed decrease in all treatments and the bacterial population showed an increase. Microbial population and nutrients of SMS were used as biaumentador and bio-stimulator in the diesel biodegradation.

 

Pre-treatment Of Peanut Hulls With Lemon Peel Waste And Cola Soda To Remove Lead

Julia Mariana Márquez-Reyes and Katiushka Arévalo-Niño

  • Abstract

    The use of agricultural residues and food industry has been increasing in recent decades, using them in the process of environmental improvement. The aim of this study was to pretreatment peanut hulls with lemon peel waste (EL1) and residues of cola soda (EL2) for promoting acid hydrolysis (HA) at different temperatures and contact times to remove lead in aqueous medium. The removal percentage of EL1 increased compared with EL2, both treatments are more efficient than controls with untreated peanut shells. The best treatment of EL1 and EL2 (85 °C, 10 min) were chosen based on the percentage removal of 98% and 92%, respectively. At low pH values Pb removal increases, the peanut shell has the ability to retain more than 50 mg Pb/L and this is directly proportional to the amount of peanut shell used (0.1 g – 0.5 g). The pre-treatment of peanut hull with lemon peel or cola soda waste is an economic, viable and sustainable alternative to be used in bioremediation of metal contaminated water.

 

Biosorption Behavior Of Non Living Aspergillus sp Biomass In lead Removal

Pedro Antonio Escobedo Hinojosa, Julia Mariana Márquez Reyes, Verónica Almaguer Cantú, Carlos Solís Rojas, Katiushka Arévalo Niño

  • Abstract

    Alternative pollutants removal and/or recovery methods are being considered which are based on sequestering properties of certain natural materials of biological origin. Biosorption can be an efficient low-cost process to remove toxic heavy metals because it covers a large surface area, uses an effective ion exchange and has selective adsorption of heavy metal ions. Biological materials have emerged as an economic and eco-friendly option. Biological treatment, based on living or non-living microorganisms or plants, offers some advantages, such as low operating cost and high efficiency. Fungi have a high percentage of cell wall material that shows excellent metal-binding properties and exhibit marked tolerance towards metals and other factors such as low pH. This study was undertaken to determine the lead biosorption potential of nonliving Aspergillus sp. biomass, under different conditions. There were no differences at two temperatures (28 ° C and 35 ° C), reaching 15% of lead removal at both conditions. Similar results were found at 100 and 150 rpm with 22% of lead removal. The highest removal was observed at pH 4.0 with 75%. However, 50% of lead was removed from an initial concentration of 10 mg/L and the maximum amount of biomass used was 0.4g. By other hand, at this biomass concentration the removal was not changed when the contact time increased. Finally, the Langmuir isotherm model, showed a correlation coefficient (R2 = 0.955), qmax value of 10.38 mg g-1 and K of 4.72 mg L-1

 

Isolation And Characterization Of Ligninolytic Bacterial Strains Present In Tropical Forest Soils

Elda Ramírez-Martínez, Edgar Querubín Aquino-Medina, Francisco J. Gabino-Román, Elizabeta Hernández-Dominguez, Alejandro G. Nila-Méndez

  • Abstract

    Lignin is a complex heteropolymer consisting of methoxilated and nonmethoxilated phenylpropanoid subunits linked to cellulose and hemicellulose. Due to the fact that lignin is a recalcitrant biomolecule to degradation, crop plant waste with high lignin content is difficult to process and convert to carbohydrates suitable for fermentation. In this work, we present isolated ligninolytic bacterial strains from tropical soils. An amount of 10 isolates were identified as lignin degraders coming from soils found in a mexican tropical region. Biochemical and molecular techniques were employed to characterize these ligninolytic bacterial strains. Dyes with similar chemical structure to lignin (e.g. malachite green [MG]) were employed as substrates for these lignin degrading isolates using both liquid and solid-phase assays. Isolates showed a dye degradation spectrum: some of them proved to be total MG degrading strains; others, just partial degraders that generally just absorbed the dye. Bacterial DNA from selected isolates was extracted, and PCR products for the 16S RNA gene were generated. These amplicons were partially sequenced and nucleotide blasted against the whole NCBI nucleotide collection. Isolate 1 reported a 100% homology to the environmental bacterium NCK210a04CL while isolate 2 reported the same level of homology to proteobacterium clone MS074A1_G09.

 

Application of Two Organic Fertilizers Obtained from Anaerobic Digestion of Pig and Cow Manure on Tomato and Chard Crops

Edgar Bustos, Diego Reyes, Myrna Solís, Erik Ocaranza, Lilia Tapia, Dalia Castillo

  • Abstract

    Anaerobic digestion is a microbial degradation process of the organic matter, the principal product is the biogas which contains carbon dioxide and methane, and a byproduct, the digestate, which is the final liquid effluent and it has been used as a fertilizer. In this work was set up two 120 L biodigesters, one fed with cow manure, and other with pig manure, both designed at 7% dry solids basis; they were maintained at mesophilic conditions (25 to 35°C) during 78 days, the biogas production and methane content was monitoredweekly. At the end of the experiment it was determined the phytotoxicity of the cow liquid digestate (CLD) and the pig liquid digestate (PLD) over lettuce seeds, and tested their efficiency as fertilizers in tomato and chard crop. They were applied on foliage at 50% and compared with: a commercial organic fertilizer (Ctrl+), a commercial phytohormones concentrate (FerA), and a control using only water (Ctrl). Only the anaerobic digestion of cow manure produced a flammable biogas (methane >40%). CLD and PLD were not phytotoxics at concentrations lower than 10% in lettuce seeds. For tomato crop, CLD showed the highest yield, getting 90% more performance than Ctrl and 16% more than Ctrl+, with a similar production cost. Using FerA and PLD was obtained similar yield between them and higher than Ctrl. While in chard crop, using the PLD was obtained the highest yield, getting 47% more performance than Ctrl and 63% more than Ctrl+; using CLD was obtained more yield than FerA, but less yield than Ctrl. Digestates were different depending on the organic matter used for the anaerobic digestion, and it could be used as fertilizers of different crops because each plant has different nutritional requirements.

 

Antibiotics Susceptibility in Enterobacteriaceae Isolated Usumacinta River, Mexico

 Ma. Concepción de la Cruz-Leyva, Thelma Olán-Santos, Temani Durán-Mendoza, Araceli González-Burgos, J. Ulises González-de la Cruz

  • Abstract

    Antimicrobial resistance is a threat to public health, involving every day new bacterial resistance mechanisms and different species. Most reported as resistant strains derived from clinical isolates and there are few studies with environmental antibiotic resistant strains. The aim of this investigation was to study antimicrobial resistance in Enterobacteriaceae isolated in the Usumacinta upper river basin, Tabasco, Mexico. Sampling seven sites with anthropogenic impact on the river basin were established during the dry season (April-May) 2013. The isolation and microbial characterization was performed by the plate culture method, recommended by Mexican standards. By disk diffusion method of Kirby-Bauer susceptibility profile of 12 antibiotics was evaluated (Amikacin-AK, Ampicillin-AM, Levofloxacin-LEV, Cephalothin-CF, Ceftriaxone-CRO, Chloramphenicol-CL, Gentamicin-GE, Netilmicin-NET, Nitrofurantoin-NF, Cefepime-FEF, Trimethoprim-sulfamethoxazole-SXT, Cefotaxime-CTX).Strains of E. coli, Salmonella sp and Klebsiella sp showed an antimicrobial sensitivity of 82.43±28.8, 81.77±32.1 and 78.33±29.5 % respectively; being AK, LEV, GE, and FEF NET antibiotics showing larger sensitivity profile (98.48±1.5 %). Furthermore, the AM was exhibited greater antimicrobial resistance gender Klebsiella sp (92 %) and Salmonella sp (100 %).The results obtained in this investigation, is one of the first reports on antimicrobial resistance of

 

Microbial Diversity Shifts During the Bioremediation of a Heavy Crude Oil-contaminated Soil at Microcosm

German Zafra1, Angel E. Absalón, Todd D. Taylor, Diana V. Cortés-Espinosa

  • Abstract

    In this study we analyzed by a metagenomic approach some of the effects (e.g. displacement, permanence, disappearance) produced between native microbiota and a hydrocarbon-degrading microbial consortium during the bioremediation of a soil polluted with hydrocarbons. Microcosm systems were prepared using a non-sterile heavy crude oil-contaminated soil, inoculated with a fungal/bacterial degrading consortium and biostimulated with sterile corn stover for 30 days under aerobic conditions. Paired-end whole genome sequencing was performed using an Illumina MiSeq platform. Metagenomic unassembled reads were analyzed and annotated in MG-RAST. Results were visualized with both the MG-RAST and MEGAN5 platforms. Taxonomic analysis of metagenomic data showed a predominance at the domain level of Bacteria and a lesser portion of Eukaryotic and Archaeal sequences. Soil inoculation with the microbial consortium resulted in appreciable shifts in microbial communities when compared to uninoculated controls. The largest differences were observed in hydrocarbon-degrading bacterial communities (Firmicutes, Actinobacteria, Proteobacteria), particularly by day 30. Fungal communities were more stable with Ascomycota being the dominant phyla, although differences with respect to controls were also observed. In conclusion, Inoculation with a degrading consortium produced appreciable changes on the microbial diversity of hydrocarbon-contaminated soils, shifting some native microbial communities to favor hydrocarbon-degrading populations.

 

Hexavalent Chromium Removal by a Penicillium sp. Fungal Strain Isolated from Environment

Damaris Arévalo, Juan F. Cárdenas, María de Guadalupe Moctezuma, Víctor M. Martínez, Ismael

  • Abstract

    The present study reports a Penicillium sp. fungal strain that exhibits high reduction potential of Cr (VI). The effect of varying pH (4.0, 5.3, and 7.0, maintained with 100 mMol/L citrate phosphate buffer.) on the rate of Cr (VI) removal, show a pH optimum of 5.5 (77% at 7 days, 28oC, and 100 rpm), while at pH of 4.0 and 6.2 were of 43% and 65%, respectively. Too, we analyzed the influence biomass in the removal capacity of Cr (VI). From the analyzed 72, 141, and 169 mg of dry weight the removal capacity was in the order of 35%, 49%, and 60%, respectively. In the presence of glucose, another inexpensive commercial carbon sources like unrefined sugar and brown sugar or glycerol, the decrease in Cr (VI) levels occurred at a similar rate, at 7 days of incubation, are of 52%, 96%, 100%, and 17%, respectively. Incubation of the biomass in the absence of a carbon source did not produce any noticeable change in the initial Cr (VI) concentration in the growth medium. These observations indicated that in culture of the fungus a carbon source is required to provide the reducing power needed to decrease Cr (VI) in the growth medium.

 

Expression Profile of Dye Decolourising Peroxidase DyP Genes from Pleurotus ostreatus Grown in Submerged Fermentation Supplemented with Textile Dyes

Soley Nava, Cristhian Pérez., Alfredo Herrera., Rubén Díaz., Gerardo Díaz., Martha Bibbins.,

  • Abstract

    Extensive research efforts have been dedicated to characterize expression of ligninolytic enzymes produced by several fungal species. The DyP (for dye decolorizing peroxidase) family constitutes a novel class of haem peroxidases. They exhibit a significant catalytic versatility resulting in oxidation of a wide range of substrates, including dyes, high redox potential anthraquinones and derivatives not oxidized by other peroxidases, which brings about possibilities of their utilization in biotechnological and environmental applications. In this research the expression profile of the white rot fungus Pleurotus ostreatus DyP genes were determined during growth and decolourization kinetics in submerged fermentations in the presence of either Remazol Brilliant Blue R (RBBR) or Acetyl Yellow G (AYG) dyes. Both dyes induced the expression of all tested genes however, the expression level fluctuated in each monitored growth phase. The highest induction was observed for 4°DyP gene in the presence of AYG dye. Patterns generated for each peroxidase gene, suggest that the 4°PO-DyP in conjunction with 2°PO-DyP genes contribute to the decolourization of the dyes. Furthermore enzymatic and molecular studies of DyP produced by P. ostreatus could contribute to have enzyme selection criteria leading to the development of effective bioremediation methods.

 

Photoacoustic Spectroscopy Analysis of the Ultrasonic Irradiation Effect on Aquatic Lirium (Eichhornia Crassipes) Plants

Jeniffer Calderón, Antonio Calderón, Alejandro Cardona, Leslie Salazar, Alejandro Rojas, Bruno Rojas, Gustavo Juárez, Ernesto Marín, Rocío Casañas, Rocío Muñoz

  • Abstract

    Aquatic Lyrium, o Water Hyacinth (WH), is a free float plant native of the Amazon, Brazil, which by the beauty of its flowers has been propagated to almost all the tropical and sub-tropical regions of the world. This plant is a weed, which causes many consequences extremely unfavorable for the environment and for the diverse human activities that are developed in the bodies of water. Among the most used methods to control water hyacinth, we will have the herbicides, physical removal or drainage, and biological control, none of which has been entirely efficient or profitable. It is for these reasons that arises the need to incorporate other new technologies of control, being in this case the use of US irradiations, with certain values of frequency and intensity, in order to induce cavitation in the aqueous structure of Aquatic Lirium, and consequently, inhibit their PS activity, causing its death. The leaves of aquatic plants are systems particularly useful for studying the effects of bubbles trapped within their structures. For this reason, in this work it was used the PA technique as a function of time by monitoring the PS activity in Aquatic Lirium plants, without irradiation and after ultrasonic irradiation.

 

In silico Analysis of Clones Sequences Showing Esterase Activity

Muñoz-López J., Chi-Manzanero B., Apolinar-Hernández M., Canseco- Pérez M., De los Santos-Briones C., O’ connor-Sánchez A., Prieto-Davó A., Rojas-Herrera R., Rivera-Muñoz G., Canto-Canche B.

  • Abstract

    A metagenomic library was constructed from Yucatán aquifer, we are searching for esterases clones by functional screening using tributyrin- based selective medium. We screened 27 000 clones and found 12 positive clones, with halo formation sequencing was performed on a pool of the clones, five supercontig´s we assembled corresponding to 4 clones, two contigs corresponding to a single clones. Other clones have not assembled so far probably because problems during sequencing.Contigs rank from 29 to 33 Kb and contain one or until three predicted open reading frames esterases, larger homology was found with Sphingobium; putative esterase shares 90% homology and in other regions decline to 80%. Therefore these sequences belong to another bacterium, probably related with Sphingobium.Much information is still required to know the identity of these microorganisms but they seem to by esterases producers in Yucatán aquifer.

 

Cloning Of Microbial Lipase Of A Metagenomic Library Of Aquifer From Yucatán

Castro Avilés Jaime, Chi Manzanero B, Ramos Jiménez S, Canseco Pérez M, De los Santos Briones C, Apolinar Hernández M, Rivera Muñoz G, Prieto Davó A, Rojas Herrera R, O’ Connor Sánchez A, Canto Canche B.

  • Abstract

    The microbial lipases represent an important group of enzymes for biotechnological applications, given that they are specific for certain substrates, stable in organic solvents and they have a high regio-enantioselectivity. The strategy implemented was a screening of a metagenomic library of the Yucatan’s aquifer, with the objective of finding lipase genes. We analyzed 6600 clones on selective medium containing rhodamine B and olive oil, obtaining 15 positives clones that showed lipolytic activity, among these, we selected the clones with biggest fluorescent halos on plate screening. Afterwards it was purified for the sequencing and supercontig of 32 kb was assembled. By using bioinformatics tools we found the predicted ORFs for some hypothetic proteins and sequences with no hits. Further Blast analysis retrieved a sequence of phospholipase from Fusarium Oxysporum, however the E-value denoted that data possibly is not reliable, reason why we will search the lipase sequence by lose of function though the use of transposition in vivo. Likewise, we will know if the data obtained by bioinformatics analysis is true.

 

Toxicity Assessment of Cobalt Nanoferrite on Wheat Seedlings

M. Camacho–Martínez, O. F. Mijangos–Ricardez1, S. Martínez–Vargas, M.C.Cuevas–Díaz, F.A. Solís–Domínguez, M.C.A. González–Chávez5 and J. López–Luna

  • Abstract

    Toxicity assessment of 2.5 nm cobalt ferrite nanoparticles (NPs) was conducted onwheat seedlings, using quartz sand as growing support. Root length of wheat plants decreased with nanoferrite concentrations (0-8000 mg/kg). Toxicological parameters were EC50 4000 mg/kg, NOAEC 1000 mg/kg, LOAEC 2000 mg/kg and MATC 1500 mg/kg. The shoot growth was not importantly affected by cobalt nanoferrite. Thus, only NOAEC could be calculated, which corresponded to 8000 mg/kg, the highest concentration assayed. Heavy metal accumulation was higher in roots than shoots, recording 264–3618 μg/g total Fe and 30–2667 μg/g total Co for ferrite treatments ranging from 0to 8000 mg/kg. Otherwise, shoot accumulation was 90–353 μg/g total Fe and 0–249 μg/g total Co. The cobalt nanoferrite was found to exert very low toxicity. Fe and Co accumulation in vegetal tissues suggested nanoferrite uptake by wheat seedlings, although mechanisms are actually unknown.

 

Analysis of Anaerobic Digestion Process from Cow Manure with and Without Temperature Control and Time Differences on Manure Storage

Lucia Cabrera-Baez, Lilia Tapia-López, Myrna Solís-Oba, Erik Ocaranza-Sánchez

  • Abstract

    Anaerobic digestion involves degradation of organic materials such as animal manure, and it is generated a product known as biogas, whose main components are carbon dioxide and methane (if methane content is >40% the biogas is flammable). Methane production depends of the anaerobic digestion process conditions.In this study we analyze the effect of the process temperature and the manure storage time, for the anaerobic digestion process and their implications over the biogas yield and its content of methane.Anaerobic digestion experiments were developed at a controlled temperature of 30°C±2 and at greenhouse conditions, without temperature control. In order to evaluate the manure storage time effect the reactors were feed with fresh and non-fresh cow manure. Experiments were replicate during three year seasons.

    We found that at 30°C and using fresh manure during the anaerobic digestion was produce biogas with at least 50% methane content, on the other hand there was not important methane quantity in biogas when non-fresh manure was feed.At greenhouse conditions and with fresh manure biogas has lower than 40% methane content and only 11% methane with the use of non-fresh manure.Biogas production and methane content was enhanced using fresh manure for the anaerobic digestion and at controlled temperature conditions (30oC)

 

Marine Bacteria With Antagonic Activity Against Biofouling Forming Bacteria

Javier Casas Venegas, Libia Lizarraga Toral, Ruth N. Aguila Ramírez

  • Abstract

    Biofouling process occurs as succession of several organisms, from bacteria to invertebrates and has severe economic impacts over port and shipping infrastructures. This succession depends on the colonization success of microorganisms, so that controlling microfouling is often the solution to manage the whole process. Moreover, bacteria are known to produce antagonistic substances (Hughes and Fenical, 2010). Over the past few years, application of these natural compounds has aroused great interest in industry to prevent biofouling. In this study, we isolated bacteria with potential activity from different marine substrates (sediments, mangrove, invertebrate, algae). Bioassays of inhibitory activity by the well diffusion method were performed. Plates were cultured with biofouling forming bacteria; the medium where bacteria isolate grew was placed in wells made using a punch. The presence of inhibition halos was observed. One hundred and thirteen bacteria were isolated with which the antagonism bioassays were performed. It was found that 31 bacteria were active against biofouling forming bacteria; fourteen of them had activity against 3 or more strains. It was found that several strains of marine origin mainly from marine sediments and mangrove may have potential on its use for biofouling control.

     

 

Chemotaxis Studies Of Pseudomonas putida KT 2440 And Mutants In Chemoreceptors For Efficient Colonization Of Tomato Plants

Dalia Juárez-Hernández, Tino Krell, Andrés Corral-Lugo, A. Laura Hernández-Tenorio, Y. Elizabeth Moráles-García, Rocío Bustillos-Cristales y Jesús Muñoz-Rojas.

  • Abstract

    An alternative for increasing the yield of crops is the use of PGPR, for this purpose the colonization is a critical process. In this work the chemotaxis toward tomato plants and bacteria colonization were evaluated for P. putida KT2440 and mutant strains in specific chemoreceptors for GABA and succinato. Axenic seedlings of three days were placed at one end of the recipients with soft agar (3g / L) and the opposite end vertically inoculated 100 μl of the explored bacterial strain and the number of CFU/ml for 1-6 days after sowing was recorded. At 3 days post-inoculation mcpG mutant showed less efficient colonization than wild type and mcpS mutant. At 4 days post inoculation two mutant strains were affected in colonization, while 6 days only mcpG-strain was affected. When the wild type and mutant strains mcpG- were coinoculated in chemotaxis systems, again was observed decreased colonization ability for the mutant strain. The mutation in the McpG and McpS chemoreceptors affect the colonization process. Chemotaxis is vital for efficient rhizosphere colonization which could have implications for growth promotion purposes.

 

Static And Agitated Aspergillus tamarii Solid State Fermentation On Coffee Pulp In A Ribbon Mixer

Isaías Nava, Ernesto Favela-Torres, Gerardo Saucedo-Castañeda

  • Abstract

    A previously described solid-state fermentation bioreactor with helical ribbons was used to growth Aspergillus tamarii on coffee pulp as substrate. Respiration and headspace temperature profiles under static and intermittently agitated (every three hours) conditions are compared and discussed. No difference was found in terms of total carbon dioxide production. However, the maximum rate of carbon dioxide production was significantly higher (32%) under agitation conditions during the cultivation. The Gompertz model was accurately used to describe the respiration profiles under both conditions. The specific rate of carbon dioxide production, an equation parameter of the Gompertz model, was similar under static and agitated culture conditions. The highest increase in the headspace temperature was obtained for the bioreactor under agitated conditions. Therefore, intermittent agitation promotes heat transfer from the solid material to the headspace without damaging the respiration of the fungi. The obtained resulted demonstrate that under intermittent agitation, this type of bioreactor could be used to perform fermentations at bigger scales.

     

 

Wastewater Odor Depletion Using Two Bacterial Strain From 20 De Noviembre Lift Station

I.I. González-Castro, J. Rodríguez Rosales, C. Cruz Fierro, R. Lucho, F.S. Hernández Rodarte

  • Abstract

    The sulfide compounds are common in wastewater treatment this causes troubles like nuisance odors. Sulfide formation jointly with H2S is responsible of associate odor to organic compounds with sulfur. The aim of this project was to evaluate the effect of two strains in wastewater odor depletion. Mineral medium was used for the isolation of strains. Selected strains were morphologically identified and Gram stain tested. Subsequently the sulfides decreasing capacity of each strain were determined in synthetic wastewater assay. From this assay were selected 3 strains (AC5, AL4 and AS25). These strains were combined in pairs (AL4-AC5, AC5-AS25 and AL4-AS25), the decreased ability sulfide was determined for each strain. In order to find the best combination, slope was determined in a log graphic of [S] mg/L. The evolution of sulfide concentration in wastewater samples from ¨20 de Noviembre¨ lift station showed a marked decline in the sample inoculated with the couple AL4-AC5, coinciding with low turbidity in relation to the uninoculated wastewater sample. The computed slope for each combination were AL4-AS25 = - 0.0273, AC5-AS25 = - 0.0234, AL4-AC5 = - 0.028, Uninoculated = 0.0054. The best performance was the pair AL4-AC5 with a slope of - 0.028.

 

Hydrogen Sulfide Production UsingSulphate-Reducing BacteriaFrom Marine Sediments

Muriel González-Muñoz, Ruby Valdez-Ojeda, Roberto Briones-Gallardo, Blondy Canto-Canché, Jorge Ramírez-Prado.

  • Abstract

    Hydrogen sulfide (H2S) produced by sulfate-reducing bacteria (SRB) is an attractive alternative to generate renewable energy. SRB are quite accessible as they are ubiquitous in marine sediments nevertheless its potential to produce H2S at laboratory conditions has not been thoroughly assessed. Three different sediments (S1, S2 and S3) were used as inoculum in Postgate’s B medium to evaluate its H2S production capacity. We found that H2S production reached the stationary phase more rapidly in S1 cultures, followed by S3 and S2, with a final concentration of 140, 220 and 366 ppm, respectively. S1, S2 and S3 achieved 59, 100 and 84% of theoretical conversion of sulfate to sulfide and a sulfate reduction rate of 0.67, 0.69 and 0.34 moles of sulfate per mole of lactate. Theoretical sulfate reduction rates are of 0.5 and 1.5 for incomplete and complete oxidation. Therefore a mixture of both types of SRB is expected in S1 and S2. Finally, the sulfide production rate was 0.4, 0.7 and 0.3 moles of sulfide per mole of lactate consumed for S1, S2 and S3, correspondingly. According to results, S2 cultures showed the best performance for H2S production, suitable for renewable energy generation.

 

Sugarcane as an Energetic Crop for the Transformation of the Productive Matrix in Ecuador

Alejandro Gallardo

  • Abstract

    The current transformation of the productive matrix in Ecuador implies the change from a pattern of raw material exports and extractive to one of diversified production, eco-efficient, and with higher added value, as well as services base on the knowledge economy and biodiversity. One of the main axles for this transformation is the Productive Diversification which includes: Biofuels, Mariculture, Forest and Strategic Industries. From here, the objective of this investigative work to establish that it is possible to produce biofuels (bioethanol), with processing plants based on energy crops (sugarcane) found in Ecuador, that not only produce food (sugar), but also material residue (bagasse) for cogeneration and other residue for fertilization processes.

    In conclusion, once zoned and distributed along the country the new fields of energy crops and distillation plants for bioethanol; not only will a new agro-environmental culture will be begin, but the new era of biofuels will start, changing the productive matrix in Ecuador and the preparation for the post-oil era. Nevertheless, to keep the sustainability of this project, it is recommended to keep excess in the production of sugar cane in order to not alter the food chain

 

Degradation of Phenol in Vinasses From The Production Process of Mezcal in a Rotating Disk Photocatalytic Reactor

R. S. Gines Palestino, D. Cantú-Lozano1 and C. Montalvo Romero 

  • Abstract

    This research shows phenol degradation effect on vinasse from mezcal production process, in rotating disk photocatalytic reactor using titanium dioxide as catalyst TiO2 ) the residence time is 72 h, took sample every 8 hours for quantifying phenol according Folin-Ciocalteau method in order to monitoring the degradation, in the same way was monitoring the concentration of dissolved oxygen present in the sample. After 50 hours the decrease in phenol concentration is observed. Photocatalytic degradation experiments obtained high percentages of degradation and mineralization of phenol in vinasse from mezcal industry.

 

Determination of a Bacterial Consortium in a Reductive Dehalogenation Process

Bastida-González F., Celaya Trejo Y. López-Pérez P., Guerrero-Barajas C., Zárate-Segura P.

  • Abstract

    The microorganisms identified in the sludge belong to the following genera: Desulfovibrio, Desulfomicrobium, Clostridium, Desulfitobacterium, Dehalobacter and Sulfospirillum. All these genera of microorganisms identified in the sludge have been related to sulfate reducing conditions Desulfovibrio, Desulfomicrobium, Desulfitobacterium and Clostridium and biodegradation of chlorinated compounds, specifically by dehalorespiration which is the case for Sulfospirillum, Desulfitobacterium and Dehalobacter although some strains of sulfate reducers such as Desulfitobacterium hafniense have also been related to biodegradation of chlorinated compounds under methanogenic conditions. Sulfospirillum multivorans and Sulfospirillum halorespirans are known for their capability of using TCE or tetrachloroethylene (PCE) as terminal electron acceptors. On the other hand Desulfitobacterium and Dehalobacter have also been studied in their capability of using a chlorinated solvent (PCE) as terminal electron acceptor. The identification of Desulfotomaculum and Desulfomicrobium in syntrophy with the other bacteria, for example, the known fermenting bacteria belonging to the genus Clostridium. D. acetoxidans and carbon source by Desulfomicrobium which is a mesophilic microorganism that uses hydrogen as electron donor and acetate as carbon source during sulfate reduction. The overall conclusions of this work is the consortium could be efficient on both, sulfate and TCE biodegradation.

 

Biogas Production by Co-digestion of Tomato´s Plant Wastes and Manure

Vanesa Chicatto-Gasperín, Myrna Solís-Oba

  • Abstract

    The accumulation of organic waste from agricultural activities is a global issue, because the no controlled degradation is a source of infection and contamination of water, soil and air. Also Due to the shortage of energy resources, are being carried out projects aimed to obtain alternative energy; one of this is the production of biogas from agro-industrial wastes. The study of the anaerobic digestion process using tomato crop residues in co-digestion with cow and pig manure is presented here; considering different experimental conditions: C:N ratios of 12/1 and 20/1, with or without initial pH adjustment at 7.5, and amount of manure (20 and 50%), to generate fuel biogas (with more than 45% methane). Were performed batch anaerobic digesters at a mesophilic temperature; it was monitoring the pH, total solids (TS) and volatile solids (VS), as an indirect way of consumption of organic matter. The methane content in biogas and volatile fatty acids (VFA) in digestate were determined by gas chromatography (GC). The highest production of fuel biogas was obtained from the co-digestion of tomato crop residues with 50% cow manure, initial pH adjusted to 7.5 and the C:N adjusted at 20/1; the methane yield for this treatment was 72.93 L/kg volatile solids consumed with a methane content higher than 45% in the most of the process. In the treatments with pig manure only the modification of the C/N relation produce a increment of the methane yield.

 

Degradation of Phenol in Vinasses From The ProductionProcess of Mezcal in a Rotating Disk Photocatalytic Reactor

R. S. Gines Palestino, D. Cantú-Lozano and C. Montalvo Romero 

  • Abstract

    This research shows phenol degradation effect on vinasse from mezcal production process, in rotating disk photocatalytic reactor using titanium dioxide as catalyst (TiO2) the residence time is 72 h, took sample every 8 hours for quantifying phenol according Folin- Ciocalteau method in order to monitoring the degradation, in the same way was monitoring the concentration of dissolved oxygen present in the sample. After 50 hours the decreas e in  Phenol concentration is observed. Photocatalytic degradation experiments obtained high percentages of degradation and mineralization of phenol in vinasse from mezcal industry.

 

Determination of a Bacterial Consortium in a Reductive Dehalogenation Process

Bastida-González F., Celaya Trejo Y. López-Pérez P., Guerrero-Barajas C.,Zárate-Segura P.

  • Abstract

    The microorganisms identified in the sludge belong to the following genera:Desulfovibrio, Desulfomicrobium, Clostridium, Desulfitobacterium, Dehalobacter and Sulfospirillum. All these genera of microorganisms identified in the sludge have been related to sulfate reducing conditions Desulfovibrio, Desulfomicrobium, Desulfitobacterium and Clostridium and biodegradation of chlorinated compounds, specifically by dehalorespiration which is the case for Sulfospirillum, Desulfitobacterium and Dehalobacter although some strains of sulfate reducers such as Desulfitobacterium hafniense have also been related to biodegradation of chlorinated compounds under methanogenic conditions. Sulfospirillum multivorans and Sulfospirillum halorespirans are known for their capability of using TCE or tetrachloroethylene (PCE) as terminal electron acceptors. On the other hand Desulfitobacterium and Dehalobacter have also been studied in their capability of using a chlorinated solvent (PCE) as terminal electron acceptor. The identification of Desulfotomaculum and Desulfomicrobium in syntrophy with the other bacteria, for example, the known fermenting bacteria belonging to the genus Clostridium. D. acetoxidans and carbon source by Desulfomicrobium which is a mesophilic microorganism that uses hydrogen as electron donor and acetate as carbon source during sulfate reduction. The overall conclusions of this work is the consortium could be efficient on both, sulfate and TCE biodegradation. 

 

Biogas Production by Co-digestion of Tomato´s Plant Wastes and Manure

Vanesa Chicatto-Gasperín, Myrna Solís-Oba

  • Abstract

    The accumulation of organic waste from agricultural activities is a global issue, because the no controlled degradation is a source of infection and contamination of water, soil and air. Also Due to the shortage of energy resources, are being carried out projects aimed to obtain alternative energy; one of this is the production of biogas from agro-industrial wastes. The study of the anaerobic digestion process using tomato crop residues in co-digestion with cow and pig manure is presented here; considering different experimental conditions: C:N ratios of 12/1 and 20/1, with or without initial pH adjustment at 7.5, and amount of manure (20 and 50%), to generate fuel biogas (with more than 45% methane). Were performed batch anaerobic digesters at a mesophilic temperature; it was monitoring the pH, total solids (TS) and volatile solids (VS), as an indirect way of consumption of organic matter. The methane content in biogas and volatile fatty acids (VFA) in digestate were determined by gas chromatography (GC). The highest production of fuel biogas was obtained from the co-digestion of tomato crop residues with 50% cow manure, initial pH adjusted to 7.5 and the C:N adjusted at 20/1; the methane yield for this treatment was 72.93 L/kg volatile solids consumed with a methane content higher than 45% in the most of the process. In the treatments with pig manure only the modification of the C/N relation produce a increment of the methane yield. 

 

Enzyme Activity of Pycnopurus sp. Grown in Two Culture Media

Cervantes Muñoz, P, . Díaz-Godínez, G. Acosta-Urdapilleta, L. Villegas Villarreal Elba Cristina. Téllez-Téllez, M.

  • Abstract

    Pycnoporus sp. produces cinnabarina with antiviral and antibacterial activities. In this study the enzymatic activities of Pycnoporus was determined. The strain was grown on potato dextrose agar (PDA) and wheat straw-dextrose agar (SDA) at 25 °C. The extracellular enzyme extract was obtained by lixiviation of agar in deionized water after removing the mycelium, the extract was centrifuged at 15000 rpm for 10 min. The hydrolytic activities were reported in international units per g dry biomass (U/gX) and the laccases unit was considered as the amount of enzyme that increased one absorbance unit in the reaction mixture per min and also was reported in U/gX. The results showed higher pectinase activity values of Pycnopurus sp. grown in SDA (164 U/gX) than in PDA (96 U/gX). Xylanase  ctivities were 78 U/gX and 38 U/gX in PDA and SDA, respectively. Laccases activity was of 42 U/gX in the SDA medium and in PDA medium was three times lower. Cellulases and invertases activities were three times higher in SDA medium than in PDA medium, approximately. Protease activity was very low in both media. This strain is a wild mushroom from state of Morelos with potential of enzymes production of industrial interest and bioremediation applications. 

 

Main Microbial Community in Organic Biofilters by 16S rRNA Based PCR-DGGE Analysis

J. M. Vigueras Cortés, C. H. Hernández Rodríguez, I. Villanueva Fierro,Dr. M. A. Garzón-Zúñiga, and D.M.C. Aguilar Reyes

  • Abstract

    Biofilm processes for wastewater treatment through biofilters packed with natural fiber is an innovative technology that is applied for small generators to improve effluent quality. In order to contribute to the scientific knowledge, was identified the microbial diversity in two column of filtration material operated in series the first one under aerobic conditions and the second one with airless applying a hydraulic loading of 1.34 m3m-2d-1. The microorganisms identification was made using denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR) amplified 16S rRNA gene fragments. Metagenomic DNA was extracted, replicated, purified and sequenced. The 16S rRNA sequences were compared with GenBank libraries taxonomic by searching Basic Local Alignment Search Tool (BLAST). A collection of sequences were obtained from the Taxonomy Browser of the National Center for Biotechnology Information. Sequences were aligned with CLUSTAL X2.0.12 software and edited with the Bio Sequences Alignment Editor (BIOEDIT) software. Species diversity found in the aerated biofilters, was dominated by the Firmicutes Phylum. In biofilters no aerated dominated bacteria belonging to the alpha, gamma and epsilon Protobacteria, Firmicutes, Bacteriodetes and Actinobacteria Phylum, respectively. DGGE produced high of biodiversity richness in without air biofilters. 

 

Expression Profiles Of Genes In The Fish Danio rerio Exposed To Environmental Samples Of Atoyac River,Mexico

Ana Maria Sandoval-Villasana; Jesus Hernandez-Romano

  • Abstract

    The presence of endocrine disrupting compounds in the Atoyac river is reported more frequently, therefore is cause for concern scientific and public. They are characterized by their low biodegradability and bioaccumulate in the trophic chain. The objective of this study was evaluate the genes expression of cyp1a, hmox and vtg1 in male zebrafish after their exposure to samples coming from nine sites established in the river. The cDNA template was synthesized from RNAt. The real-time qPCR was performed using the TaqMan Universal PCR Master Mix. Our results show that the cyp1a gene increased its expression between 2.4 and 9.6 times, the hmox gene between 1.0 and 5.0 times and the vtg1 gene showed important increases of between 9.1 and 12.6 times. These genes tend to be induced or not change their expression in the different sampling points, a characteristic that marks them as potential molecular biomarker genes. The vtg1 expression suggests contributions of compounds with hormonal activity. The expression of cyp1a and hmox, both associated with redox reactions, could be related to the conversion of pollutants presents in the river and are absorbed by the fish, the oxidized forms and solubles, can be more easily excreted by the organism.

 

Analysis Of Herbicide Paraquat Degradation, By Isolated Macromycetes From Southeast State Of Chiapas

Camacho-Morales Reyna L., Andrade-Gallegos René H., y Sanchez-Vazquez José E.

  • Abstract

    In this study was to perform the isolation and characterization of macromycetes from the southern agricultural region of Chiapas in order to evaluate their potential use for bioremediation purposes of recalcitrant compounds to the environment, specifically the herbicide paraquat. 328 specimens were collected, of which 32.1% (105 specimens) were isolated. 23 fungi were identified to genus and species level and 48 to genus level. The most abundant species was Hexagonia hydnoides; and the most represented genera were Xylaria and Marasmius. All isolates were tested for laccase activity. An experiment was conducted to determine the tolerance on solid culture medium. Those strains that were tolerant were used to determine the percentages of degradation of the herbicide in the liquid culture medium at the same concentration. 10 strains with a percentage of degradation of 50 to 70% were found. These strains were monitored to determine the production of extracellular enzymes (laccase, manganese peroxidase, and aryl alcohol-oxidase), and relate the degradation of paraquat. From eight surveys made in the coffee area of El Soconusco, Chiapas, 105 strains of macromycetes were isolated. 10 strains showed an ability to degrade the herbicide paraquat (between 50-70%) in 15 days growth at 26ºC, in liquid medium. 

 

Study Of PHA Synthase Phylogenetic Trees And Operon Structures For The Optimal Production Of Industrially Relevant Polyhydroxyalkanoates

Olivia López-Ayala, Germán Alejandro Royval-García, Juan Francisco Villarreal- Chiu

  • Abstract

    Plastics are produced worldwide as high-value products. However, they have become a very important ecological problem. The biosynthesis of eco-friendly materials as an alternative to traditional plastics has become a significant topic of research. One of these alternative materials are polyhydroxyalkanoates (PHAs), which are bacterial biopolymers of high rate biodegradability. Their main drawback is the relatively high cost of production. Metabolically, a classification exists based on types of PHA synthases (enzymes responsible for the biosynthesis of PHA), substrate specificity and monomer sizes, where class II synthases produce PHAs with latex-like properties of commercial interest, unlike classes I, III and IV which produce stiff and brittle PHAs. Thus, in this work we report the categorizing of PHAs gene clusters by phylogenetic analysis as a theoretical predictive method, helpful to improve the discovery of new strains of industrial relevancy for PHAs biosynthesis. From all  ynthases, class IV was more predominant with 33%, followed by class III and II (28 and 25%). For classes III and IV, the most predominant transcriptional regulator was GntR with 19.6% and 24.9%, in contrast with the predominant transcriptional regulators OmpR for class I and AcrR and TetR for class II. 

 

Evaluation of Beauveria bassiana Hydrolytic Enzymes Produced in FSS on Cyclocephala lunulata Burm. (Coleoptera: Melolonthidae)

Lluvia de Carolina Sánchez-Pérez; Silvia Rodríguez-Navarro; Juan Esteban Barranco-Florido.

  • Abstract

    The enzymes produced by entomopathogenic fungi are potential agents for the biocontrol of pests because of their toxicity. The FSS allows the production of enzymes and it consisted of a minimum media and shrimp shell, 1x107 /ml of spores from Beauveria bassiana was inoculated. The obtaining of conidium and enzyme extract of 15 and 5 days, were  etermined

    by the enzyme activity of: lipases, proteases, endo and exo chitinases. The larva of Cyclocephala

    lunulata were injected with 10μl of each treatment, under control conditions (25±2 °C; 50% RH). In the extract of 5 days, the activity of lipases, proteases (Pr1) and (Pr2), endo and exo chitinases were observed; responsible for the degradation of the cuticle. The activity as insecticide of the enzymes was demonstrated with a mean difference of (P<0.05); the mortality was 100% in: treatment B, C and D; for E was 60% and for F was 90%; the control one was with not deaths. The time of death : with mean difference (P<0.05); B and C 1.2 days, F 1.7 days, D and E 2.8 and 8.8 days. The activity of the enzyme extract alone as insecticide was demonstrated and also with conidium of C. lunulata. 

 

Three-Phase Anaerobic Digestion System For Municipal Sludge Treatment

Agustín Rodríguez-García, Sergio Valle-Cervantes, Josefina Rodríguez-Rosales

  • Abstract

    Thermophilic anaerobic digestion systems have high efficiency for sludge stabilization. However, the problems associated with these systems (high production of volatile fatty acids and odors) results in an unstable process. Moreover, the temperature phased anaerobic systems have shown better odor control generation and pathogen reduction. The objective of this study is to analyze a system of three temperature phases, using two organic loadings. The experimental process was carried out in four batch anaerobic digesters, and the overall operation time was 33 days. Two digesters were fed with sludge containing a flocculant and the others without it. Digesters were operated at two organic loadings (0.8 and 1.6 kg Total Volatile Solids (TVS)), and three temperatures (35°C, 55°C, 35°C). Experiments 1 and 2 were running at 0.8 kg of TVS, and experiments 3 and 4 at 1.6 kg of TVS. The first mesophilic phase was for sludge acclimation. In the thermophilic phase the greatest reduction of volatile solids was observed at 0.8 kg TVS. In the last mesophilic phase the greater reduction of fecal coliforms was observed in experiments without flocculant, as well as, the greatest production of methane gas. All experiments showed reduction in volatile solids reaching the regulations of biosolids.

 

Confirmation in the Microorganisms’ Identification by Universal Primers as Taxonomic Tool at National Collection of Microbial Strains and Cell Cultures

D. A. Estrada-Bárcenas, J. Martínez-Cruz, J. C. Estrada-Mora and A. Sánchez-Chavarría

  • Abstract

    The National Collection of Microbial Strains and Cell Cultures (Colección Nacional de Cepas Microbianas y Cultivos Celulares as original name, WFCC registration CDBB-500) aims to preserve and identify reference strains and isolates of biotechnological significance. The taxonomic identification of microorganism is necessary to verify, classify and organize the different strains. The target of this work is confirm the taxonomic classification of CDBB-500 strains, sequencing with universal primers (16S for bacteria and ITS regions for fungi) and a BLAST search (NCBI software). The identification obtained was compared with the originally taxonomic classification or with the findings from the physiological and biochemical tests. A total of 86 strains were sequenced, and only 59 strains (69%) have a priori identification. The molecular identification with the universal primers confirmed the taxonomic classification of 47 strains (80%) with a match to genus and species. Five species (8%) are newly described, that is reason that taxonomic confirm was genus level. Four strains (7%), grouped on the same order, are genus with the same phenotypic characteristics. Three strains (5%) did not match, one of them has not valid classification and the other two are under study to solve the differences.

 

Dye Remotion by Fungi Treatment

D. Gallardo-Navarro, J. I. Durán-Leyva1, L. J. Galán-Wong, M. E. Alemán-Huerta, K. Arévalo-Niño, V. Almaguer-Cantú, G. Rojas-Verde

  • Abstract

    Biosorption through activated carbons or organic resins is the procedure of choice and gives the best results to remove different dyes. The fungal mycelia have an advantage over single cell organisms by producing extracellular enzymes. We evaluated the capability to biosorption/biodegradation of RBBR by three native fungi isolated in Cuernavaca, Morelos. The enzymes activities no were detected under assay condition. At 72h, PECM2H6 showed 72% of remotion, while PECM2H5, reached the maximum dye remotion with 92% at 84 hours. Finally, PECM1H1 at the same time, showed a 74% of remotion. Dye desorption was observed in all tested fungi and this suggested that the process of mechanism for decolonization was biotic, through absorption or by the activity of another enzymes.

 

Application of Plastic Waste as Substrate in Hydroponic Systems

Juan C. Alvarez-Zeferino, Diana Hernández-Barranco, Margarita Beltrán-Villavicencio, Gladys M. Aguilar-Trejo, Perla X. Sotelo-Navarro and Alethia Vázquez-Morillas

  • Abstract

    In this project styrofoam (Styrofoam), wastes from plastic bags (Plastic) and plastic films obtained from a composting process of disposable diapers (Diaper), were used as substrate in a NFT (Nutrient Film Technique) hydroponic system. The effect of the plastics was measured by evaluating the growth of lettuce (Lactuca sativa) and broccoli (Brassica oleracea). Tezontle was used as positive control. A hydroponic system with a volume of 80 L and a constant flow of 700 L/h was used during 49 days. 120 g of nutrient solution was added. The position of the samples was defined randomly. The development of plant species was evaluated in terms of dry biomass (grams), including the root and aerial parts. Broccoli grown in plastic and tezontle had the highest values of dry biomass, followed by the styrofoam while the diaper showed the lowest value. On the other hand, lettuce growth was favored using diaper as substrate, while the results of the remaining three substrates were similar. In conclusion, the use of waste plastic and styrofoam in a traditional hydroponic system allows for recovery, thereby replacing a commercial substrate (Tezontle) and getting the same or better yields.

 

Evaluation of Sulfate Reduction with Different Substrates in Sulfidogenic Sludge Enriched from Marine Hydrothermal Sediment and Adapted to Low pH.

García-Solares Selene Montserrat, Carrasco-Cándido Eréndira Adriana, Guerrero-Barajas Claudia

  • Abstract

    Sulfate reduction (SR) has been used as an alternative for the treatment of effluents containing sulfate ion (SO4-2) and a variety of organic matter. There is a wide variety of organic compounds commonly found in industrial effluents that can be used as substrates for SR, for example, ethanol, lactate, acetate, butyrate and propionate, or mixtures of these compounds. The following substrates were used: acetate, propionate, butyrate and a mixture of volatile fatty acids (VFA) acetate/propionate/butyrate, in a 1:1:1 COD proportion. Serum bottles with a total volume of 127 mL (27 mL headspace) were used. The inoculum was obtained from a UASB operated under sulfidogenic conditions. Mineral medium, vitamins and trace metals were mixed at an initial pH of 4 with sulfate (8000 mg/L) and substrate (8000 mg COD/L). Analysis for sulfate reduction, consumption of substrate (by analyzing the COD), pH, and sulfate-reducing activity (SRA) were conducted after 13 days of incubation, all the experiments were performed at ambient temperature. Sulfate reduction efficiency for the different substrates used was between 97 to 98%, the substrates consumption was 85 to 93%.The the best yield was obtained for the VFA mixture. SRA was 9.9 g COD-H2S/ g VSS*d for each substrate. Increasing pH due to the oxidation of the substrate was from 6.3 to 6.7.

 

Isolation And Characterization Of Chromogenic Bacteria For The Development Of Multiresponse Biosensors

Marco A. Méndez-González, Aurora Flores-Piña, José Altamirano-Hernández

  • Abstract

    Common genetic circuits (AND logic gated) are inefficient because they use reporter genes that need the use of special equipment to see its activity. That is why we propose a new genetic circuit model, a biosensor that can be read by the simple change of color. The objective of this work is the identification and isolation of chromogenic bacteria and the genes responsible for the synthesis of its pigments, and the creation of bacterial genetic circuits capable of detecting different heavy metals. Soil and water samples were taken at Michoacán and Puebla states. These materials were processed by the serial dilution technique, followed by inoculation in nutritive agar and tryptic soy agar at different pH. Pigmented colonies were purified. Bacterial characterization was performed by 16S rRNA genes sequencing. Bacterial pigments were characterized by GC/MS. A total of twenty-seven bacterial strains were isolated and characterized. With rRNA sequencing data we obtained a phylogenetic tree that shows a wide taxonomic diversity among these chromogenic bacteria. Characterization of pigments shows that most of them are of carotenoid nature. This work will set the basis for the development of colorimetric biosensors based on complete cells to detect heavy metals in water or food.

 

Growth of Pleurotus ostreatus and Lentinula edodes Grown in Di (2-Ethylhexyl) Phthalate in Agar

Angel González-Márquez , José Luis Torres-García, Miriam Ahuactzin-Pérez , Gerardo Díaz-Godínez , Rubén Díaz, Carmen Sánchez

  • Abstract

    Di (2-ethylhexyl) phthalate (DEHP) belongs to the phthalic acid esters. DEHP is used as plasticizer to give flexibility to polyvinyl chloride (PVC). Pleurotus ostreatus and Lentinula edodes are able to degrade lignocellulose and recalcitrant compounds due to their enzymatic machinery. The radial growth rate (ur), mycelial biomass (MB), S/R glucans ratio, protein and glycogen content, and activities of laccases and esterases were evaluated in P. ostreatus and L. edodes. Four agar culture media were prepared. 1) GYEA medium containing (in g/L): glucose 10; yeast extract, 5; KH2PO4, 0.6; MgSO4 7H2O, 0.5; K2HPO4, 0.4; CuSO4 5H2O, 0.25; FeSO4- 7H2O, 0.05; MnSO4 H2O, 0.05, ZnSO4 7H2O, 0.001 and agar, 25, 2) GYEA + 750 mg of DEHP/L, 3) GYEA + 1200 mg of DEHP/L and 4) GYEA + 1500 mg of DEHP/L. P. ostreatus and L. edodes were inoculated in the in center of the agar plates and incubated at 25 0C for 7 d. The highest MB, protein content, glycogen content, laccase and esterase activities was observed in the media containing DEHP in both fungi. These suggest that there was no catabolite repression (glucose effect) and that DEHP was used as carbon and energy source by L. edodes and P. ostreatus. The enzymatic activities increased in the media added with DEHP.

 

Depuration of Effluents of Textile Laundry Through Enzymatic Systems. Study Case: Tweed laundry Installed in Tepetitla de Lardizabal, Tlax.

Héctor Muñiz; Myrna Solis ; Jorge Meléndez 

  • Abstract

    The aim of this work was to analyze the color removal of the discharges of a textile laundry, “Laundry and dye Alonso”; this is a small industrial laundry located in Tepetitla of Lardizabal, Tlaxcala, México, which dye the tweed clothes. We took some samples of colored effluents from the most frequent process that they make. Samples were kept in cones Imhoff for a 24 hour period, after that was measured the COD change, conductivity and pH before and after of the sedimentation, just like the sediment solids and percentage % of discoloration being caught by the sedimentation. Supernatant that continue with visible color were submitted to enzymatic oxidation with laccase of the fungi Trametes versicolor, inmobilized over silica gel and packed in a column. The supernatant was passed several times through the packed column until a visible color reduction was successfully, and the % of discoloration was quantified with the absorbance’s changes. Photototoxicity in the water was evaluated before and after the enzymatic oxidation measuring the index of germination of lettuce’s seed. We found that the most frequent process in the industrial laundry is dying and this is the most phytotoxic for lettuce seeds. The discoloration after sedimentation was between 21% and 93% and increase to 46% to 100% with enzymatic oxidation. Sedimentation is a simple and cheap pretreatment to diminish the color in textile effluents.

 

Green Synthesis Of Gold Nanoparticles Using Latex Of Jacaratia Mexicana

Juan Manuel C Figueroa, Ángel Netzahuatl Lopantzi, O. Zaca Moran, A .Martínez Ayala, R. Delgado Macuil, Valentín López Gayou, M. Rojas López

  • Abstract

    We report a method for green synthesis to produce gold nanoparticles using the latex of Jacaratia mexicana obtained from the fruit of the tree by through slits, this tree is endemic of Mexico, it will take this as a reducing and stabilizer agent for obtaining nanoparticles, it was prepared with deionized water to 1% and a stock solution of the metal salt of chloroauric acid (HAuCl4) to 1mM concentration of the mixture at a ratio of 6:4 respectively, the synthesis was obtained using a bottom-up technique in constant agitation. The first evidence for the synthesis of nanoparticles was the change in coloration of the medium to pink-ruby red after 15min and confirmation by uptake patterns characterization by UV / visible spectroscopy with an intense characteristic peak of the surface plasmon at ∼575nm. So the use of latex of Jacaratia mexicana represents a non-toxic, economical and eco friendly method of biochemical synthesis of gold nanoparticles.

 

Using of Fluorescence Spectroscopy to Characterize Organic Matter in the Effluent from a Nitrifying Reactor

Sagnite Ventura and   Mario Esparza

  • Abstract

    Fluorescence spectroscopy is an analytical tool used to examine water samples of different origin because it is sensitive, selective and can give a wide range of information on the composition, characteristics, origin and distribution of dissolved organic matter (DOM). Soluble microbial products (SMP) are organic compounds produced during growth and decay of microorganisms in biological treatment systems. SMP are important because they are formed during the biological treatment of waste water and comprise a significant portion of the DOM of the effluent of these treatment systems. The main objective of this study was to characterize the effluent of a MOD nitrifying autotrophic aerobic reactor using 3-D EEM to determine if the 3-D EEM could identify SMP produced by nitrifying bacterium. The 3-D EEM nitrifying reactor effluent showed only two fluorescence peaks (Peaks C and D) allocated to humic substances. The presence of peaks C and D in the effluent from the nitrifying reactor located at longer wave lengths and higher fluorescence intensity with respect to those observed in the influent could be attributed to the production and accumulations of SMP autotrophic nitrifying aerobic bacterium due that predominated in the reactor and are the only possible source of fluorescent DOM.

 

Effects of Nanoparticles on Plants, Microorganisms and Earthworms

Fabián Fernández-Luqueño, Fernando López-Valdez, María Fernanda Valerio-Rodríguez, Juan Luis Hernández-López, Ireneo García-Ortiz, Abraham Emmanuel Ramirez-Hernández, Betsabe Gómez-Hernández, Celeste Aide Robles-López, Javier López-Baltazar

  • Abstract

    Despite the rising numbers of peer-reviewed publications during the last years that address the environmental, health, and safety aspects of engineered nanomaterials (ENM), the implications of potential exposure of crops, microorganisms and ecosystems to this ENM is still not well known. The aim of this study was to research the effect of ZnO, Ti2O, Fe2O3 nanoparticles (NPs) on some crops (Sunflower, Helianthus annuus L.; maize, Zea mays L.; bean, Phaseolus vulgaris L.; and beet, Beta vulgaris L.), soil microorganisms, and earthworms (Eisenia fetida). SPAD units increased significantly (P<0.05) when sunflower was irrigated with Fe2O3-NPs at 6 g L-1, compared with the other treatments. Root and shoot length, shoot fresh weight, and shoot dry weight did not show significant effect on bean and maize crops when nanoparticles were added. The ZnO-, Ti2O-, and Fe2O3-NPs significantly decreased the colony-forming units of bacteria and actinomycetes when soil was spiked with NPs, but there were not significantly differences on the fungi counts. E. fetida showed obvious physical damage and significantly decreased the amount of organisms when they were spiked with Fe2O3-NPs. The growth, development and survival of some crops, soil microorganisms and E. fetida were altered when placed in contact with different doses or types of NPs, so it is necessary to develop further research for assessing ecological and environmental damage caused by the use or release of NPs.

 

Biochemical Characterization of Rhizobacteria Isolated From Several Rhizospheric Soils

Minerva Rosas-Morales, Fabián Fernández-Luqueño, Fernando López-Valdez 

  • Abstract

    The aim of this work was isolate and characterize bacteria from several soil samples of plant rhizospheres. The characterization of these microorganisms was done by root colonization, siderophores production, antagonism activity, IAA production, proteolytic activity, among others, in order to obtain a bacterial collection with PGPR characteristics. The total isolated strains were 60. The hydrolases production tests were carry out four times per duplicate. The chitinases production tests were done two times per duplicate and the results were negative for all strains tested. Antagonism assays. The antagonism assays were negative for all strains. However, it was observed a recurrent effect in almost all the Petri dishes that show an inhibition halo and low mycelium production compared with Control (only the fungal strain). The enzymatic activity of proteases was positive in 90% of all the isolated rhizobacteria strains tested. The production chitinases tests were negative in all strains. Some rhizobacteria strains showed an antagonist effect, however, these results were not conclusive due to that measure of inhibition halo was weak. Siderophore production, eight strains produced siderophores of 20 strains. The halo diameters were measured between 0.5 to 1 cm. Five strains are candidate as PGPR from total of 60 strain isolated.

 

Application Of Spent Mushroom Substrate Of A. Bisporus For The Bioremediation Of Soils Contaminated With Hydrocarbons

Amparo Mauricio-Gutiérrez, Ana Lilia González-Sorcia, Teresita Jiménez-Salgado, Lucía López-Reyes, Armando Tapia-Hernández

  • Abstract

    Agricultural soils from Acatzingo, Puebla, Mexico have been impacted by oil spills; therefore it is necessary to recover. The spent mushroom substrate (SMS) of Agaricus bisporus has been reused on the bioremediation. This research aimed to determine the diesel´s biodegradation in agricultural soil using SMS. Soil and SMS were characterized physicochemically and microbiologically. Microcosm experiments were carried with different doses of non-sterile SMS (5, 10, 15 and 20%) and sterile soil contaminated (7039 ppm diesel) incubated at 25 and 37oC for 28 d; CO2 production, diesel´s biodegradation, and initial and final population cultivable of bacteria and fungi tolerant at diesel were determined. Soil contained 2.04% organic material, 0.032% total nitrogen and 0.00256% phosphorus; and SMS presented 57.6%, 1.46% and 0.79% respectively. The soil had generally a higher number of cultivable microbial populations (6.02, 5.04, 4.04 and 2.90 Log cfu/gss bacteria, diesel-tolerant bacteria, fungi, and actinomycetes respectively). In microcosm experiments treatments incubated at 37oC showed higher biodegradation and CO2 production. With 15% of SMS the highest biodegradation was obtained (68.75 %). Fungi population showed decrease in all treatments and the bacterial population showed an increase. Microbial population and nutrients of SMS were used as biaumentador and bio-stimulator in the diesel biodegradation.

 

Isolation and Molecular Identification of Clostridium sp. from an Upflow Anaerobic Sludge Blanket Reactor

Martha Patricia López-Cervantes, Martha Elena Esteva-García, Ricardo Waldo1 and Erika T. Quintana

  • Abstract

    It is well known that many industries produce compounds that are recalcitrant, resistant to degradation and may persist many years in the environment. These compounds are present in the industrial residual water and may contain ethanol, methanol, volatile fatty acids, sulfate ions and chloride compounds. The microbial diversity plays an important role in the biosphere as decomposers of organic material and in the biochemical cycles. Some microbes are specialized in sulfate reduction and degradation of xenobiotic compounds, and due to this capacity new technologies have been developed, particularly the Upflow Anaerobic Sludge Blanket reactors (UASB). The aim of the present work was to isolate and identify members of the genus Clostridium from an UASB reactor. The isolation was carried out using a primo isolation experiment and the Anaerogen system. Media were inoculated from a sample of sediment from an UASB reactor in sulfhidogenic conditions. The organism was then cultivated in nutrient agar. DNA was extracted and the 16S rRNA gene amplified by PCR. The BLAST analysis showed that isolate belongs to the genus Clostridium. The organisms is Gram positive, produces endospores, is white, dry, circular, convex, with entire borders, smooth surface and about 2-3 mm in diameter. The phylogenetic analysis indicated that the closest organism is Clostridium sargatoforme. This study represents in Mexico the first of its kind in the isolation in pure culture of obligate anaerobic bacteria of the genus Clostridium from an UASB reactor.

 

Bioremediation of Soil by Using Bagasse Oil Palm and Coffee Husk

Oswaldo Guzmán-López, Clara Ivonne Ruiz-Reyes, Adriana Hernández-Ordaz,María del Carmen Cuevas-Díaz

  • Abstract

    The alternative of adding agro-industrial waste in soil bioremediation processes could reduce their costs. These residues have the function of improving the characteristics of the soils and are considered as low density materials that can improve the physical, chemical and biological characteristics of soil. The objective of this study was to remove the total petroleum hydrocarbons (TPH) by using residues of coffee husk or bagasse oil palm (Elaeis guineensis). These residues could increase the porosity of soils, it could enhance the oxygen diffusion which favors the hydrocarbonoclastic activity, the soil stability and structure. A system of bioremediation in micro-scale (100 g) was used with different mixtures of contaminated soil and bagasse oil palm, these were placed in with ratios of 100:0, 98:2, 96:4 and 92:8. Respective controls in the treatments were employed. Treatments were incubated at 28 °C, aeration was verified subjecting every third day with an air flow of 8 L/min. Experiments were carried out during 30 days. The response variables were TPH, CO2 production and total count of microorganisms. The used conditions of the biological process accelerate the bioremediation, the addition of 2% of coffee husk and 4 % of bagasse oil palm are recommended in future studies.