Caracterización de un Consorcio Microbiano Metanogénico de una Mina de Carbón en la Cuenca de Bogotá / Characterization of a Methanogenic Microbial Consortium from a Coal Mine in Bogotá Basin

RESUMEN En el trabajo se estudió un consorcio microbiano metanogénico de una mina de carbón de la cuenca de Bogotá en Colombia. Se establecieron cultivos de enriquecimiento de carbón ex situ para el crecimiento y la producción de gas de novo. El gas biogénico producido por los cultivos se analizó mediante cromatografía de gases con detectores de ionización de llama y conductividad térmica. Los cultivos se utilizaron para aislar estirpes microbianas y para generar bibliotecas del gene 16S rARN empleando de cebadores de bacteria y de arquea. El análisis de cromatografía de gases mostró producción de metano a 37 oC, pero no a 60 oC, donde el CO2 fue el componente principal del gas biogénico. El análisis de la secuencia del gen 16S rARN de estirpes microbianos y de las bibliotecas de clones, estableció que el consorcio microbiano metanogénico estuvo formado por especies de bacterias de los géneros Bacillus y Gracilibacter más la arquea del género Methanothermobacter. El consorcio microbiano metanogénico identificado es potencialmente responsable de la generación de gas biogénico en la mina de carbón La Ciscuda. Los resultados sugirieron que los metanógenos de este consorcio producían metano por vía hidrogenotrófica o de reducción de CO2.

ABSTRACT The work studied the methanogenic microbial consortium in a coal mine from the Bogotá basin in Colombia. Ex situ coal-enrichment cultures were established for in vitro growth and de novo gas production. Biogenic gas produced by cultures was analyzed by gas chromatography using thermal conductivity and flame ionization detectors. Cultures were used to isolate microbial specimens and to generate 16S rRNA gene libraries employing bacterial and archaeal primer sets. The gas chromatographic analysis showed methane production at 37 oC, but not at 60 oC, where CO2 was the major component of the biogenic gas. 16S rRNA gene sequence analysis of microbial isolates and clone libraries established that the methanogenic microbial consortium was formed by bacteria species from Bacillus and Gracilibacter genera plus archaea from the Methanothermobacter genus. This meth-anogenic microbial consortium was potentially responsible for biogenic gas generation in La Ciscuda coal mine. The results suggested that these methanogens produced methane by hydrogenotrophic or CO2 reduction pathways.

Tillage and nutrient management influence net global warming potential and greenhouse gas intensity in soybean-wheat cropping system

Conservation tillage has proven advantageous in improving soil health and productivity. However, the greenhouse gases (GHGs) emission and intensity from different conservation tillage and nutrient management systems under Indian conditions are less understood. Therefore, here, we compared the effect of tillage and nutrient management on GHGs emissions, net global warming potential (NGWP), and greenhouse gas intensity (GHGI) from a field experiment under five years in a soybean-wheat cropping system in the Vertisols. The tillage treatments comprised of reduced tillage (RT) and no tillage (NT). The three nutrient management treatments included application of 100% NPK (T1), 100% NPK + 1.0 Mg FYM-C ha-1 (T2), 100% NPK +2.0 Mg FYM-C ha-1 (T3). The results showed significantly higher SOC sequestration under NT (1388 kg ha-1 yr-1) followed byRT (1134 kg ha-1 yr-1) with application of FYM (2.0 Mg C ha-1) (T3) every year. Across tillage, integrated nutrient management(T2 and T3) lowered NGWP and GHGI compared to NPK (T1). The GHGI of NT system was less by 33% compared to RT. The results suggest that GHGs mitigation and sustained food production in the soybean-wheat system can be achieved in NT and RT with integrated use of organic and inorganic fertilizer as the major component of nutrient management.

Pasture management and greenhouse gases emissions

Pastures are important environments worldwide because they offer many ecosystem services and sustain meat and milk production. However, pastures ecosystems are responsible for greenhouse gas (GHG) emission. The major GHGs include CO2, CH4, and N2O. The present review summarizes GHG emission from pasture ecosystems and discusses strategies to mitigate this problem. In pastures, emissions originate from animal excretion, fertilization, and organic matter decomposition. Emissions of specific gases can be measured based on certain factors that were recently updated by the United Nation's Intergovernmental Panel on Climate Change in 2019. Urine is the main source of N2O emission. Forage structure is an important factor driving GHG transport. Forage fiber content and animal intake are the key drivers of enteric CH4 emission, and the introduction of forage legumes in pasture systems is one of the most promising strategy to mitigate GHG emission.

The relationship between methane production metabolic flux and microorganisms in a microbial electrolytic cell coupled anaerobic digestion / 生物工程学报

In this study, voltage was used as a disturbance factor to investigate the relationship between microbial community and methane (CH4) production flux in a microbial electrolytic cell coupled anaerobic digestion (MEC-AD). Metabolic flux analysis (MFA) was used to explore the relationship between the CH4 metabolic flux produced and the microbes. The results showed that both methane production flux and hydrogen production flux changed significantly upon voltage disturbance, while the voltage disturbance had little effect on acetic acid production flux. The maximum CH4 production flux under 0.6 V disturbance was 0.522±0.051, which increased by 77% and 32%, respectively, compared with that of the control group under 1.0 V (0.295±0.013) and under 1.4 V (0.395±0.029). In addition, an average of 15.7%±2.9% of H2 (flux) was used to reduce CO2 to produce CH4 and acetic acid, and an average of 27.7%±6.9% of acetic acid (flux) was converted to CH4. Moreover, the abundance of Lachnospiraceae significantly affected the flux of acetic acid. The flux of CH4 production is positively correlated with the abundances of Petrimonas, Syntrophomonas, Blvii28, and Acinetobacter, and negatively correlated with the abundances of Tuzzerella and Sphaerochaeta. The species that affected the flux of H2 and CH4 were similar, mostly belonging to Bacteroides, Clostridium, Pseudomonas and Firmicutes. Furthermore, the interspecies interaction is also an important factor affecting the MEC-AD methanogenesis flux.

Engineering application of aerobic methane oxidizing bacteria (methanotrophs): a review / 生物工程学报

Aerobic methane oxidizing bacteria (methanotrophs) can use methane as carbon source and energy source, eliminating 10%-20% of global methane. Methanotrophs can also effectively synthesize valuable methane-derived products. This article introduced the methane oxidizing mechanism of methanotrophs, and summarized the practical application and research hotspots of methanotrophs in the field of methane emission reduction in the landfill, ventilation air methane mitigation in coal mines, valuable chemicals biosynthesis, as well as oil and gas reservoir exploration. Main factors influencing the pollutant removal and the biosynthesis efficiency in various applications were also discussed. Based on the study of large-scale cultivation of methanotrophs, some measures to benefit the application and promotion of aerobic methane oxidizing biotechnology were proposed. This includes investigating the effect of intermediate metabolites on methanotrophs activity and population structure, and exploiting economical and efficient alternative culture media and culture techniques.

Effects of polypharmacy on small intestinal bacterial overgrowth in elderly subjects / 中华老年医学杂志

Objective:To investigate the effect of multiple medications on the risk of small intestinal bacterial overgrowth(SIBO)in the elderly.Methods:Clinical data of 85 inpatients in the Department of Geriatrics, the First Hospital of Lanzhou University undergone HMBT from August 2017 to April 2021 were retrospectively analyzed.According to the HMBT results, they were divided into a SIBO(+ )group and a SIBO(-)group.Polypharmacy was defined as ≥ 5 types of medications.We analyzed the difference in the rate of polypharmacy between the two groups.Results:A total of 85 hospitalized elderly patients were included in the study.Of these patients, 38(44.71%)tested positive for SIBO.Polypharmacy occurred in 41 patients(48.24%). There were significant differences in types of drugs and polypharmacy between the SIBO(+ )group and the SIBO(-)group( t=3.01 and χ2=14.33, P<0.05 for both). Moreover, polypharmacy was a risk factor for SIBO( P=0.017, OR=10.85, 95% CI: 1.52-77.29). Among 14 commonly used drugs, gastrointestinal motility drugs were closely related to SIBO.There was a positive correlation between polypharmacy and the change in hydrogen levels at 90 min( P=0.040, r=0.22, 95% CI: 0.01-0.42). Conclusions:Polypharmacy is correlated with SIBO in the elderly, is a risk factor for SIBO and is helpful in clinical practice to assess the risk of SIBO and decide further examinations, contributing to early diagnosis and early treatment.

Influência de diferentes tipos de nanopartículas de prata na biodegradação da fração orgânica de resíduos sólidos urbanos / Influence of different types of silver nanoparticles on the biodegradation of the organic fraction of municipal solid waste

RESUMO Os resíduos sólidos urbanos (RSU) contêm aproximadamente 50% de fração orgânica (FO), que, por meio de processos de biodegradação em aterros sanitários, resultam em lixiviados e biogás. A degradação anaeróbia ocorre impulsionada por processos microbianos realizados por um consórcio complexo de micro-organismos, responsáveis pelas diferentes fases. Por outro lado, observa-se que as nanopartículas (NP), especialmente as de prata (NPsAg), vêm sendo cada vez mais utilizadas em novos produtos. Assim, os RSU podem apresentar materiais nanoparticulados, que, depositados em aterros sanitários, se comportam de maneira ainda pouco conhecida, podendo influenciar os processos de biodegradação. Os objetivos do presente trabalho são analisar e verificar o potencial metanogênico de resíduos sólidos orgânicos com e sem a interferência de diferentes concentrações e tipos de NPsAg. Para isso, foram realizados ensaios do potencial biometanogênico com as concentrações de 5, 15, 45, 50, 150 e 450 mg NPsAg.kg−1 RSU e comparados com a amostra padrão (branco). Diferentes tipos de nanopartículas foram utilizados: sólido (em pó), solução em base aquosa e em base alcoólica com álcool polivinílico (PVA). Os resultados mostram que, em concentrações altas (150 e 450 mg NPsAg.kg−1), as NPsAg tendem a diminuir a atividade dos micro-organismos metanogênicos. Finalmente, a modelagem dos resultados mostrou que o modelo logístico se ajusta bem aos dados experimentais. A regressão linear entre os parâmetros desse modelo e a concentração de NPsAg demonstram o decréscimo dos parâmetros com o aumento na concentração desses compostos.

ABSTRACT Municipal solid waste (MSW) contains approximately 50% of organic fraction (OF), which through landfill biodegradation processes results in leachate and biogas. Anaerobic degradation occurs driven by microbial processes, with a complex consortium of microorganisms, responsible for different phases. On the other hand, it is observed that nanoparticles (NPs), specially silver nanoparticles (AgNPs), have been appearing in a large range of new products. The MSW, for example, can present nanoparticulate materials, which, deposited in landfills, behave in a way still little known in science, and that can influence the biodegradation processes. The objective of this work is to analyze and verify the biochemical methanogenic potential of organic solid waste with and without the interference of different concentrations and types of AgNPs. For that purpose, tests of biochemical methane potential (BMP) with the concentrations of 5, 15 and 45, 50, 150 and 450 AgNPs mg.kg−1 were carried out and verified through a standard sample (white). Different types of nanoparticles were used: solid (powder), and two solutions, aqueous and alcoholic (polyvinyl alcohol — PVA). The results showed the interference of AgNPs in the highest concentrations used, considerably decreasing the biological process measured through the activity of microorganisms in the production of methane gas, which occurred in the range between 150 and 450 mg.kg−1 of AgNPs. Finally, the statistical studies and the mathematical modeling of the results showed that the logistic model adjusted well to the experimental data. The linear regression of the model parameters with the concentration of AgNPs demonstrates the decrease in the values of the parameters with the increase in the concentration of these compounds.

Effect of methane on acetaminophen-induced acute liver injury in mice and role of autophagy / 中华麻醉学杂志

Objective:To evaluate the effect of methane on acetaminophen-induced acute liver injury (ALI) in mice and the role of autophagy.Methods:Forty clean-grade SPF healthy adult male C57BL/6 mice, aged 8-10 weeks, weighing 20-25 g, were divided into 4 groups ( n=10 each) using a random number table method: control group (group C), group ALI, methane-rich saline group (group MS) and methane-rich saline plus 3-methyladenine (3-MA) group (group MS+ 3-MA). Acetaminophen 300 mg/kg was injected intraperitoneally to establish ALI model.Group MS was injected intraperitoneally with methane-rich saline 10 ml/kg immediately after establishing the model and at 12 h after establishing the model.Group MS+ 3-MA was injected intraperitoneally with methane-rich saline 10 ml/kg and autophagy inhibitor 3-MA 30 mg/kg immediately after establishing the model and was injected intraperitoneally with methane-rich saline 10 ml/kg at 12 h after establishing the model.The equal volume of sterile saline was given intraperitoneally at the same time points in C and ALI groups.At 24 h after establishment of the model, blood samples from the eyeball were taken for measuring concentrations of alanine transaminase (ALT) and aspartate transaminase (AST) in serum (using biochemistry analyzer) and the concentrations of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in serum (using enzyme-linked immunosorbent assay). The animals were then sacrificed and liver tissues were removed for determination of microtubule-associated protein 1 light chain 3 (LC3) and p62 (by Western blot) and for the examination of the number of autophagosomes (under a transmission electron microscope). Results:Compared with group C, the concentrations of ALT, AST, TNF-α and IL-6 in serum were significantly increased, LC3Ⅱ/LC3Ⅰ ratio was increased, expression of p62 was up-regulated, and the number of autophagosomes was increased in liver tissues in ALI, MS and MS+ 3-MA groups ( P<0.05). Compared with group ALI, the concentrations of ALT, AST, TNF-α and IL-6 in serum were significantly decreased, LC3Ⅱ/LC3Ⅰ ratio was increased, expression of p62 was down-regulated, and the number of autophagosomes in liver tissues was increased in group MS, and AST concentration in serum was decreased and LC3Ⅱ/LC3Ⅰ ratio was increased in group MS+ 3-MA ( P<0.05). Compared with group MS, the concentrations of ALT, AST, TNF-α and IL-6 were significantly increased, the LC3 II/LC3 I ratio and the number of autophagosomes were decreased in lung tissues in group MS+ 3-MA ( P<0.05). Conclusion:The mechanism by which methane can reduce acetaminophen-induced ALI is related to enhancement of the level of autophagy in liver cells in mice.

Synthesis, bioactivity evaluation of dibenzoyl methane halophenols and their interactions with CAV-1 / 药学学报

Caveolin-1 (CAV-1) is related to inflammation, oxidative damage, and immunity. In order to obtain a series of dibenzoylmethane halophenols with strong anti-inflammatory and antioxidant effects targeting CAV-1, twenty-nine target compounds were therefore synthesized by Baker-Ventaraman rearrangement and demethylation reaction, starting from the substituted benzoyl chloride and o-hydroxyacetophenone, and their interactions with CAV-1 were investigated by BLI technique. Their in vitro anti-inflammatory and antioxidant properties were also evaluated. The results showed that compounds A6, A17, A18, and A29 not only specifically bind to CAV-1, but also present strong anti-inflammatory and antioxidant effects. These results suggest that this class of compounds can affect the signaling pathways related to inflammation and oxidative stress by directly acting on CAV-1. In particular, these compounds exhibit the most significantly inhibitory effects on IL-1β and COX-2 release. IL-1β plays a key regulatory role in the development of arthritis. Therefore, it is worth expecting for the application of such compounds in the prevention and treatment of arthritis.

Bioconversion of methane by metabolically engineered methanotrophs / 生物工程学报

Due to abundant availability of shale gas and biogas, methane has been considered as one of the most potential carbon sources for industrial biotechnology. Methanotrophs carrying the native methane monooxygenase are capable of using methane as a sole energy and carbon source, which provides a novel strategy for reducing greenhouse gas emission and substituting edible substrates used in bioconversion processes. With the rapid development of genetic engineering tools and biosynthesis techniques, various strategies for improving the efficiency of methane bioconversion have been achieved to produce a variety of commodity bio-based products. Herein, we summarize several important aspects related with methane utilization and metabolic engineering of methanotrophs, including the modification of methane oxidation pathways, the construction of efficient cell factories, and biosynthesis of chemicals and fuels. Finally, the prospects and challenges of the future development of methane bioconversion are also discussed.

Co-digestión anaerobia de la fracción orgánica de residuos sólidos urbanos y su lixiviado / Anaerobic co-digestion of the organic fraction of urban solid waste and its leachate

RESUMEN Los residuos sólidos urbanos (RSU), al ser vertidos sin tratamiento apropiado, ocasionan daños severos al medio ambiente influyendo en la calidad de vida de la población; por esta razón actualmente se le presta atención al adecuado manejo de estos residuos. En este trabajo se estudia la reducción de la fracción orgánica (FORSU), de residuos sólidos generados por un grupo poblacional, tomando como referente una de las residencias estudiantiles de la Universidad de Oriente. La generación de FORSU en la residencia es de 0,06 kg/habdía, con un contenido de sólidos totales de 30,9 ± 5,3 %, de los cuáles el 81,7 ± 0,6 % son sólidos volátiles. Se evalúa la digestión anaerobia la FORSU, mediante un sistema de tratamiento en dos etapas. La primera etapa se realiza en un reactor en lote de lecho escurrido, que permitió un tratamiento discontinuo e in situ de la FORSU, en co-digestión anaerobia con un 25 % de estiércol vacuno. En una segunda etapa, se evalúa el tratamiento anaerobio para los lixiviados que se generan en el reactor en lote, empleando un reactor UASB. En el reactor en lote se alcanzó una remoción de sólidos volátiles del 44,1 %, mientras que en el reactor UASB se removió un 81,2 % de DQO. Como resultado la evaluación del sistema de tratamiento, se alcanzó una productividad total de 5,37 LCH4-kgSV -1-d-1.

ABSTRACT Urban solid waste (MSW), when are discharged without proper treatment, causes severe damage to the environment, influencing the population's quality of life. For this reason, attention is currently paid to the proper handling of this waste. This paper studies the reduction of the organic fraction of solid waste (OFMSW), generated by a population group, taking as reference one of the Student Residences of the Universidad de Oriente. The generation of OFMSW in the residence is 0.06 kg/inhabday, with a total solid content of 30.9 ± 5.3%, of which 81.7 ± 0.6% are volatile solids. The anaerobic digestion of OFMSW is evaluated through a two-stage treatment system. The first stage is performed in a drained-bed batch reactor, which allowed discontinuous and in-situ treatment of OFMSW, in anaerobic co-digestion with 25% of cow manure. In a second stage, the anaerobic treatment for the leachates generated in the batch reactor is evaluated, using a UASB reactor. In the batch reactor a removal of volatile solids of 44.1% was achieved, while in the UASB reactor 81.2% of COD was removed. As a result of the evaluation of the treatment system, total productivity of 5.37 L CH4 -kgSV -1-d-1 was achieved.

Potential of microbial inoculum from buffalo feces in activating lignite coal bed methane

Aim: This research aimed to study the ability of microbial consortium from buffalo feces to produce coal bed methane (CBM) in lignite coal through in-vitro technique.Methodology: This study was carried out in 2 stages: In first stage, microbes activated using in-vitro technique, and at second stage volatile fatty acids (VFA) and coal bed methane production were estimated. The nutrition source for inoculum activation was of three types: 100% concentrate: 70% concentrate: 30% grass and 30% concentrate: 70% grass. Biogas digester in laboratory-scale utilized 100 ml serum bottle filled with 70 ml, 98-5 media and 7 g coal. Microbial inoculum was inoculated on digester using a 10 ml syringe and incubated at 39oC. Parameters observed to measure the quality of inoculum were total number of anaerobic microbes, kinetics, and biogas production during fermentation. Complete Randomized Design with two factorial consisted of incubation period as factor A and inoculum dosages as factor B. Results: The activation process of inoculum from buffalo feces was required to produce coal bed methane in anaerobic digestion. During activation process, the microbes from buffalo feces in a mixture of 70% concentrate and 30% grass at 48 hr observation could produce total gas approximately 22.5 ml at 48 hr observation. Addition of activated buffalo feces anaerobic inoculum on the anaerobic digestion as much as 6% produced the highest number of anaerobic bacteria, and VFA accounted for 31 x 1010 CFU ml-1 and 171.7 mM, respectively. Meanwhile, the highest methane production reached 128.61 ml on adding 6% inoculum

Emissões fugitivas de biogás em camada de cobertura de solo compactado em aterro sanitário / Fugitive emissions of biogas in coverage liner of compacted soil in a landfill

RESUMO As emissões fugitivas de biogás podem representar parcela significativa do fluxo de gases em aterros sanitários, inviabilizar o aproveitamento energético do metano (CH4), além de oferecer riscos à saúde ambiental das comunidades circunvizinhas ao empreendimento. Nesse contexto, este trabalho teve por objetivo avaliar as emissões fugitivas e os fatores que interferem no fluxo de biogás em camada de cobertura final (liner) de aterro sanitário. A área de estudo consistiu em uma célula de resíduos, com massa de 62.359,44 t de resíduos sólidos urbanos (RSU) depositados, no aterro sanitário de Campina Grande, Paraíba, Brasil. Nessa célula, foram realizadas medições das emissões fugitivas de biogás, por meio da metodologia de placa de fluxo estática, análises das concentrações de gases na interface solo-resíduo, utilizando dispositivos de medição de concentração de gases (DMC) e mapeamentos das emissões de gases na célula de resíduos, aplicando técnicas de interpolação de dados baseada na Krigagem. Foram verificados fluxos de CH4 e dióxido de carbono (CO2) variando de 0 a 0,09 e 24,62 a 331,31 g.m-2.dia-1, respectivamente. O percentual de retenção do CH4 e do CO2 pela liner foi elevado, acima de 95%, sendo influenciado principalmente pelo elevado grau de compactação (GC) médio obtido para a célula (91,84%) e pela eficiência do sistema de drenagem de gases. O mapeamento das emissões de biogás na célula de resíduos mostrou-se uma ferramenta importante na identificação das áreas com maior potencial de geração e de fluxo de biogás pela camada de cobertura.

ABSTRACT Fugitive biogas emissions can represent a significant part of the gas flow in landfills, make the methane (CH4) energy use unfeasible, and also pose risks to the environmental health of the surrounding communities. In this context, this work aimed to evaluate the fugitive emissions and the factors that interfere in the biogas flow in the final landfill liner. The study area consisted of a Waste Cell, with a mass of 62,359.44 t of MSW deposited at the Campina Grande Sanitary Landfill, Paraíba, Brazil. In this Cell, measurements of the fugitive emissions of biogas were carried out, using the static chamber methodology; analysis of the concentration of gases at the soil-waste interface, using Gas Concentration Measurement Devices (CMD); and mapping of the gas emissions in the Waste Cell, applying data interpolation techniques based on Kriging. Flows of CH4 and carbon dioxide (CO2) ranging from 0 to 0.09 and 24.62 to 331.31 g.m-2.day-1, respectively. The percentage of retention of CH4 and CO2 by the liner was high, above 95%, being influenced mainly by the high degree of average compaction obtained for the Waste Cell (91.84%) and by the efficiency of the gas drainage system. The mapping of biogas emissions in the Waste Cell proved to be an important tool in the identification of the areas with the greatest potential for biogas generation and flow through the cover liner.

Genetic diversity of 16S rRNA and mcrA genes from methanogenic archaeas

Methanogenic archaeas are found in aquatic and terrestrial environments and are fundamental in the conversion of organic matter into methane, a gas that has a potential use as renewable source of energy, which is also considered as one of the main agents of the greenhouse effect. The vast majority of microbial genomes can be identified by a conservative molecular marker, the 16S ribosomal gene. However, the mcrA gene have been using in studies of methanogenic archaea diversity as an alternative marker, highly conserved and present only in methanogens. This gene allows the expression of the enzyme Methyl-coenzyme M reductase, the main agent in converting by-products of anaerobic digestion into methane. In this context, we aimed to study the genetic diversity of mcrA and 16S rRNA genes sequences available in databases. The nucleotide sequences were selected from the NCBI. The heterozygosity and molecular diversity indexes were calculated using the Arlequin 3.5 software, with plots generated by package R v3.0. The diversity and heterozygosity indices for both genes may have been influenced by the number and size of the sequences. Descriptive analysis of genetic diversity generated by sequences deposited in databases allowed a detailed study of these molecules. It is known that the organisms in a population are genetically distinct, and that, despite having similarities in their gene composition, the differences are essential for their adaptation to different environments.

Therapeutic effect of methane and its mechanism in disease treatment / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Methane is the simplest hydrocarbon, consisting of one carbon atom and four hydrogen atoms. It is abundant in marsh gas, livestock rumination, and combustible ice. Little is known about the use of methane in human disease treatment. Current research indicates that methane is useful for treating several diseases including ischemia and reperfusion injury, and inflammatory diseases. The mechanisms underlying the protective effects of methane appear primarily to involve anti-oxidation, anti-inflammation, and anti-apoptosis. In this review, we describe the beneficial effects of methane on different diseases, summarize possible mechanisms by which methane may act in these conditions, and discuss the purpose of methane production in hypoxic conditions. Then we propose several promising directions for the future research.

The effect of introduction of chicken manure on the biodiversity and performance of an anaerobic digester

Background: Ammonium stress is a prime limiting phenomenon that occurs during methane formation from poultry manure. It is caused by elevated ammonium nitrogen concentrations that result from substrate decomposition. The amounts of methane formed depend on the activity of methanogenic microbes. Results: During the research reported in this paper, the response of a mesophilic consortium inhabiting a biogas reactor to rising load of poultry manure was investigated. The taxonomic composition of bacterial population was mostly typical, however syntrophic bacteria were not detected. This absence resulted in limitation of succession of some methanogenic microorganisms, especially obligate hydrogenotrophs. The methanogenic activity of the consortium was totally dependent on the activity of Methanosaeta. Inhibition of methanoganesis was noticed at ammonium nitrogen concentration of 3.68 g/L, total cessation occurred at 5.45 g/L. Significant amounts of acetic acid in the fermentation pulp accompanied the inhibition. Conclusions: The effectiveness of the consortium was totally dependent on the metabolic activity of the acetoclastic Methanoseata genus and lack of SAOB did not allow hydrogenotrophic methanogens to propagate and lead to cessation of biogas production at an elevated ammonium concentration at which acetoclastic methanogens were inhibited.

Evaluación de producción de biogás y reducción de carga orgánica de vinazas mediante digestión anaerobia / Biogas production evaluation and reduction of vinasse organic load by anaerobic digestion

RESUMEN La vinaza es un residuo derivado de la producción de alcohol carburante, que posee elevada carga orgánica disuelta (46%), bajo pH que oscila entre 3-5 y alta demanda química de oxigeno (DQO) de 200-300 mgDQO/L, dichas características hacen de la vinaza un potencial contaminante. Hoy en día, se han buscado métodos que contribuyan a un adecuado manejo de este residuo, como su aprovechamiento para generar energía. En esta investigación se determinó el efecto de la concentración de vinaza y el tipo de lodo inoculante sobre la tasa global de producción de biogás, actividad metanogénica y reducción de carga orgánica durante el proceso de digestión anaerobia. Se utilizaron lodos como fuente de inóculo, provenientes de una PTAR, de una laguna de vinaza, y de laguna de oxidación y enfriamiento; la producción de biogás se cuantificó con la técnica de desplazamiento de líquido, se determinó la actividad metanogénica específica (AME), se determinó la tasa de remoción de DQO y sólidos totales y se aislaron microorganismos metanogénicos. Se encontró que la concentración de 90% de vinaza con lodos de la laguna de oxidación obtuvo los mejores rendimientos, se cuantificó 674.5 mL de biogás durante 1 8 días en un volumen de trabajo de 400 mL y se calculó la AME de 0.2 gDQOCH4/gSSV.d. Se demostró que a partir de la digestión anaerobia reduce un 25.2% de la DQO y 22.4% de sólidos; los resultados del análisis microbiológico permitieron evidenciar la presencia de microorganismos metanogénicos en el biorreactor anaerobio.

ABSTRACT Sugarcane vinasse is a residue derived from the production of fuel alcohol, that has a high dissolved organic load (46%), pH ranging from 3 to 5, and chemical oxygen demand (COD) from 200 to 300 mg/l. These characteristics make of the vinasse a potential contaminant. Therefore, methods have been sought that contribute to an adequate management of this waste, such as its use to generate energy. In this research, the process of anaerobic digestion of sugarcane vinasse and sludge as inoculant was evaluated based on the global rate of biogas production, methanogenic activity and reduction of organic load. Different concentrations of vinasse and different sources of sludge were tested; WWTP biosolids, vinasse sludge, and sludge from oxidation and cooling lagoon. Biogas production was quantified by technique liquid displacement, was determined the specific methanogenic activity (SMA), removal of COD and total solids were also determined, and isolation of methanogenic microorganisms. It was determined that the concentration of 90% of vinasse with sludge from the oxidation and cooling lagoon produced the highest yield; 674.5 mL of biogas was quantified during 18 days in a work volume of 400 mL and the SMA of 0.2 g DQOCH4 / gSSV.d was calculated. It was demonstrated that the anaerobic digestion it reduces 25.2% of COD and 22.4% of solids, the results of the microbiological analysis allowed to demonstrate the presence of methanogenic microorganisms in the anaerobic biorreactor.

Estudo da atividade metanogênica específica de diferentes lodos anaeróbios / Study of specific methanogenic activity of different anaerobic sludges

RESUMO O estudo da atividade metanogênica específica (AME) constitui uma importante ferramenta para o controle operacional de reatores anaeróbios, pois apresenta parâmetros de monitoramento da eficiência e estabilidade de um reator biológico. Nesse sentido, o presente trabalho visou determinar a AME de lodos provenientes de reatores anaeróbios de fluxo ascendente (UASB - upflow anaerobic slugde blanket) de duas indústrias cervejeiras (lodos A e B), uma de processamento de grãos (lodo C), uma leiteira (lodo D) e uma de processamento de couro (lodo E). Os ensaios foram conduzidos em batelada, em ambiente aclimatado a 35°C, utilizando um equipamento para monitorar a geração de biogás em função do tempo de digestão. Também foi realizada a qualificação do gás metano presente no biogás gerado pelos diferentes lodos. O maior valor de AME obtido e a maior porcentagem do gás metano produzido, para uma concentração de biomassa de 5,0 gSTV.L-1 e 4,0 gDQO.L-1 de glicose, foram para o lodo B: 0,36 gDQO-CH4.gSTV-1.d-1 e 58,9%, respectivamente.

ABSTRACT The study of Specific Methanogenic Activity (SMA) is an important tool for operational control of anaerobic reactors, as it presents parameters to monitor the efficiency and stability of a biological reactor. For this reason, the present article aimed to determine the SMA of sludges from UASB reactors, of two different brewing industries (sludges A and B), a grain processing industry (sludge C), a dairy industry (sludge D), and a leather processing industry (sludge E). Assays were performed in batch, at an acclimatized environment (35°C), using a device equipment to monitor the generation of biogas due to digestion time. Also, the quantity of methane gas was measured in the biogas generated by the different sludges. The best SMA value obtained and the greater percentage of methane gas generated, with a biomass concentration of 5.0 gSTV.L-1, and a glucose concentration of 4.0 gCOD.L-1, were for sludge B, with 0.36 gCOD-CH4.gSTV-1.d-1 and 58.9%, respectively.

Reducción de metano in vitro con el glucósido cianogénico Linamarina / Reduction of in vitro methane with the cyanogenic glucoside Linamarin

RESUMEN Objetivo. Evaluar el efecto de dosis crecientes del glucósido cianogénico Linamarina, en la reducción de metano ruminal in vitro. Materiales y Métodos. Se empleó líquido ruminal de dos ovejas fistuladas de la raza Merino Precoz, con el que se inoculó un sustrato fermentativo constituido por heno de alfalfa (Medicago sativa) y grano de avena molido (Avena sativa L.), se adicionó solución buffer y Linamarina (pureza de ≥98%) en dosis crecientes, lo que se llevó a incubación por ocho horas in vitro. El metano se midió cada hora, con un monitor de gases infrarrojo. Resultados. De acuerdo con el incremento de las dosis de Linamarina (0, 6, 13, 20 y 26 mg/L), la concentración de metano disminuyó de forma lineal (p≤0.05) en (9.7, 9.2, 18.1 y 29.4%) respectivamente. Se observó una reducción significativa de metano con la dosis más alta de Linamarina. Conclusión. La Linamarina, en su estado puro, fue eficaz en la reducción de metano durante la fermentación ruminal in vitro. Por lo tanto, este estudio constituye una base para futuros experimentos que incluyan fuentes vegetales de Linamarina y otras variables ruminales, lo que puede conducir a encontrar estrategias para reducir los gases de efecto invernadero.

ABSTRACT Objective. To assess the effect of rising doses of the cyanogenic glucoside Linamarin on the reduction of in vitro rumen methane. Materials and methods. Rumen fluid from two fistulated Merino Precoz sheep, inoculated with a fermentation substrate comprising alfalfa hay (Medicago sativa) and ground oat grain (Avena sativa L.), and added with buffer solution and Linamarin (purity ≥98%) in rising doses, was incubated for eight hours in vitro. Methane was measured each hour with an infrared gas monitor. Results. According Linamarin doses were increased (0, 6, 13, 20 and 26 mg/L), the methane concentration fell in a linear manner (p≤0.05) by (9.7, 9.2, 18.1 and 29.4%), respectively. A significant reduction of methane was seen whit the highest dose of Linamarin. Conclusions. Linamarin, in pure state, was effective to reduce methane during in vitro ruminal fermentation. Therefore, this study constitutes a basis for future experiments including vegetable sources of Linamarin as well as other rumen variables, leading to find a strategy for reducing greenhouse gases.

In vitro Evaluation of Corn Germ Meal as Ruminant Feed

The present study was taken up to assess the chemical composition and in vitro nutritional worth of corn germ meal (CGM) in comparison to conventional oilseed cakes used in livestock feeding. The CP content of protein sources varied from 18.59% in CGM to 49.41% in soybean meal (SBM). CGM had the highest ether extract (EE) content, neutral detergent fibre (NDF), acid detergent fibre (ADF) and total carbohydrates. However, total ash, acid detergent insoluble crude protein (ADICP) and neutral detergent insoluble crude protein (NDICP) was lowest in CGM. In vitro net gas production in CGM (267.91 ml/g DM/24 h) was higher (P<0.05) than other conventional oil cakes. The digestibility of organic matter varied from 85.12% in DMC (deoiled mustard cake) to 96.19% in SBM. The ME availability was highest (P<0.05) in CGM (9.63 MJ/kg DM). Ammonical nitrogen in CGM was lower (P<0.05) than SBM and GNC (groundnut cake).The total volatile fatty acids (TVFA) production (mM/dl) was highest (P<0.05) in GNC (12.56) and lowest (P<0.05) in CGM (9.31). Methane production was lowest (P<0.05) in CGM than other conventional oil cakes. Hydrogen recovery (%) was higher (P<0.05) in CGM (65.76) and SBM (65.78) than other protein sources tested. Fermentation efficiency (%) was higher (P<0.05) in SBM (77.02) and GNC (76.75) while volatile fatty acids utilization index (VFA UI) was higher (P<0.05) in CGM (2.92) and DMC (2.84) than other protein sources tested. The results revealed that CGM can be used as a potential protein source for ruminants.