Biodegradation Of Substances Research Articles

Competition for electrons between pyridine and quinoline during their simultaneous biodegradation.

Biodegradation of pyridine and quinoline is initiated with mono-oxygenation reactions that require an intracellular electron donor. Simultaneous biodegradation of both substrates should set up competition for the intracellular electron donor that may inhibit one or more of the mono-oxygenation steps. An internal circulation baffled biofilm reactor (ICBBR) was used to evaluate the impacts of competition during pyridine and quinoline biodegradation. Compared with independent biodegradation, pyridine and quinoline removal rates were slowed when biodegraded simultaneously, although the pyridine removal rate decreased more than for quinoline. The first mono-oxygenation of quinoline (to 2-hydroxyquinoline) always was faster than the first mono-oxygenation of pyridine (to 2-hydroxypyridine), and the difference was accentuated with pyridine and quinoline which were biodegraded simultaneously due to the competition for intracellular electron donor. Competition also existed between the second mono-oxygenations, and the removal rate of 2-hydroxypyridine was faster than the rate for 2-hydroxyquinoline, even though the rate was faster for quinoline than pyridine. Adding an exogenous electron donor accelerated all mono-oxygenations in proportion to the amount of donor added, but the increments were greater for quinoline due to its higher affinity for intracellular electron donors than pyridine. When actual coking wastewater was used as the background matrix, removals of pyridine and quinoline exhibited the same competitive trends.

Degradation Model of Micro-polluted Raw Water by Enhanced Biological Filtration

As an important research area in drinking water treatment field, biofiltration and the mathematical modeling has received considerable attention. Butthe model does not match the experimental study. For designing the biofiltration process the practical model is not available. The objective of the study is to develop a representative model which simulates NOM (natural organic matter) removal in water treatment biofilter. A steady-sate model and the Monod-type substrate utilization were applied. The external and internal mass transfer was neglected in this model. The process of substrate biodegradation, bacterial attachment onto filter media and detachment of suspended bacteria was described. The NOM and biomass profiles in a biofilter as a function of filter depth and filtration velocity was simulated. Through a special experiment the key biokinetic parameters and Ks were estimated. Test and calculation results show that the model predictions are in good agreement with the experimental data. The model adapts to a wide range of various conditions by changing the parameters such as flow rate, bacteria and DOC concentration et al.

Nutrient and Physiological Requirements for Biomass Production of Pestalotiopsis sp. UMAS P14 and Pseudopestalotiopsis sp. UMAS P2005/2592

Fungi are important decomposers in our ecosystem and are useful in metabolite production, bio-degradation and bio-sorption of different substrates and wastes through their mycelial biomass. Fungal species are known to have different preferences for their growth requirements. Two fungal species Pestalotiopsis and Pseudopestalotiopsis useful in many biotechnological applications were studied. Nutrient and physiological requirements for mycelial biomass production such as carbon and nitrogen, pH, light and temperature were investigated. Both fungal isolates were grown in liquid basal medium supplemented separately with various carbon and nitrogen source and incubated under different light, pH and temperature conditions for 15 days. In general, Pestalotiopsis sp. and Pseudopestalotiopsis sp. showed significant preferences for monosaccharide and disaccharide carbon source as compared to sugar alcohols and polysaccharides, whereas ammonium tartrate was more preferred as a nitrogen source compared to ammonium nitrate, ammonium sulphate and other ammonium salts. These two fungal species were able to grow and produce good mycelial biomass (223.33 mg for Pseudopestalotiopsis and 136.67 mg for Pestalotiopsis) at temperature range of 15°C to 30°C and (290.00 mg for Pseudopestalotiopsis and 256.67 mg for Pestalotiopsis) on media pH of slightly acidic to slightly alkaline. However, they showed no significant preferences between constant light, total darkness and alternate light conditions. The results from this study will be very useful for the mycelial biomass production of Pestalotiopsis sp. and Pseudopestalotiopsis sp. for their biotechnological applications.

Effect of micro-aeration and inoculum type on the biodegradation of lignocellulosic substrate

The effect of various micro-aeration strategies on the anaerobic digestion (AD) of wheat straw was thoroughly examined using a mixture of inocula, containing compost and well digested sludge from biogas plant. The aim was to determine the most efficient oxygen load, pulse repetition and treatment duration, resulting in the highest methane production. The oxygen load had the largest impact on the biodegradability of straw, among the examined variables. More specifically, a micro-aeration intensity of 10mLO2/gVS was identified as the critical threshold above which the AD performance was more susceptible to instability. The highest enhancement in biogas production was achieved by injecting 5mLO2/gVS for a consecutive 3-day treatment period, presenting a 7.2% increase compared to the untreated wheat straw. Nevertheless, the results from optimisation case study indicated a higher increase of 9% by injecting 7.3mLO2/gVS, distributed in 2 pulses during a slightly shorter treatment period (i.e. 47h).

Acidification and sulfide formation control during reductive dechlorination of 1,2-dichloroethane in groundwater: Effectiveness and mechanistic study

To enhance the reductive dechlorination of 1,2-dichloroethane (DCA) in groundwater, substrate injection may be required. However, substrate biodegradation causes groundwater acidification and sulfide production, which inhibits the bacteria responsible for DCA dechlorination and results in an odor problem. In the microcosm study, the effectiveness of the addition of ferrous sulfate (FS), desulfurization slag (DS), and nanoscale zero-valent iron (nZVI) on acidification and sulfide control was studied during reductive dechlorination of DCA, and the emulsified substrate (ES) was used as the substrate. Up to 94% of the sulfide was removed with FS and DS addition (0.25 wt%) (initial DCA concentration = 13.5 mg/L). FS and DS amendments resulted in the formation of a metal sulfide, which reduced the hydrogen sulfide concentration as well as the subsequent odor problem. Approximately 96% of the DCA was degraded under reductive dechlorination with nZVI or DS addition using ES as the substrate. In microcosms with nZVI or DS addition, the sulfide concentration was reduced to less than 15 μg/L. Acidification can be controlled via hydroxide ions production after nZVI oxidation and reaction of free CaO (released from DS) with water, which enhanced DCA dechlorination. The quantitative polymerase chain reaction results confirmed that the microcosms with nZVI added had the highest Dehalococcoides population (up to 2.5 × 108 gene copies/g soil) due to effective acidification control. The α-elimination mechanism was the main abiotic process, and reductive dechlorination dominated by Dehalococcides was the biotic mechanism that resulted in DCA removal. More than 22 bacterial species were detected, and dechlorinating bacteria existed in soils under alkaline and acidic conditions.

Research on anaerobic digestion of corn stover enhanced by dilute acid pretreatment: Mechanism study and potential utilization in practical application

The utilization of lignocelluloses for biogas production is limited for several aspects, and an efficient pre-treatment is essential to increase the enzyme accessibility of cellulose. This research focused on the mechanism of biogas production and biodegradation properties under the treatments with different acid agents, including sulfuric acid (H2SO4), acetic acid (CH3COOH), and phosphoric acid (H3PO4). The H3PO4 pretreated corn stover was then co-digested with cow dung in a pilot test to investigate the performance of acid pretreatment in practice. The results showed that the main compositions of corn stover were cellulose, hemicellulose, and lignin, and their proportions in the corn stovers were increased after the acid pretreatments. This hence increased the final biogas yields (up to 40.75%), methane content, and promoted the biodegradation process. More significantly, the acid pretreatments delayed the appearance of the peak value of the biogas yield for 3 to 8 days depending on the acid concentrations. This study proposed that the dilute weak acid pretreatment, especially H3PO4 pretreatment, efficiently enhanced the biogas production by increasing the degradation of hemicellulose. Further on, the H3PO4 pretreatment also improved the stability of fermentation, which would benefit the biogas generation in practice. This research contributes to a better understanding of the mechanism of acid influence on enhancing the biogas generation and substrate biodegradation, and provides pratically sound guidance for reclamation of lignocellulosic materials.

Biodegradation of Cellulose-Containing Substrates by Micromycetes Followed by Bioconversion into Biogas

The ability of micromycetes Trichoderma viride and Aspergillus terreus to decompose the cellulose-containing substrates was studied. Office paper and cardboard, as well as a paper mixture, were found to be the most hydrolyzable. The cellulolytic activity of T. viride was 2-3 times higher than that of A. terreus; the highest values of 0.80 and 0.73 U/mLwere obtained from office paper and the paper mixture, respectively. The micromycete cultivation conditions (composition of culture medium, sucrose cosubstrate addition, seeding method) and the conditions of the fungus biomass treatment for its subsequent bioconversion into biogas by anaerobic microbial communities were optimized. It was shown that pretreatment improves the efficiency of biogas production from lignocellulosic materials under seeding with microbial community of bovine animal manure. After pretreatment of the Jerusalem artichoke phytomass (stems and leaves) and its subsequent bioconversion into biogas by methanogenic community, the biogas yield was increased by 1.5 times.

Prediction of sustainable electricity generation in microbial fuel cell by neural network: Effect of anode angle with respect to flow direction

This study aimed to investigate for the first time the effect of anode inclination on electricity generation integrated with biodegradation of organic substrate in a mediator-less microbial fuel cell continuously fueled with actual dairy wastewater. The influence of anode inclination was investigated at angles 0, 45 and 90° with respect to the flow direction on the MFC performance with respect to power generation and COD removal, alternatively at 1 and 2mL/min wastewater flow rate. Results revealed that maximum power generation of 486 and 369mW/m2 and COD removal efficiencies of 92 and 89% were observed when the anode was positioned perpendicularly with the flow direction at steady state conditions using wastewater flow rates of 1 and 2mL/min, respectively at external resistance of 40Ω. Lower COD removal and power generation were observed for MFCs designed with anodes positioned at 0° and 45° with respect to the feed flow direction. A three-layer artificial neural network (ANN) model was investigated in this study to predict the efficiency of the MFC in regard to power generation. Results of prediction indicated a good fitting between actual and predicted data with a high correlation coefficient (R2) of 0.99889 with negligible mean square error.

Biodegradation kinetics and interactions of styrene and ethylbenzene as single and dual substrates for a mixed bacterial culture.

This study examined biodegradation kinetics of styrene and ethylbenzene as representatives of alkenylbenzenes and mono-alkylbenzenes, respectively. The compounds were studied independently and as binary mixtures using a series of aerobic batch degradation experiments introduced by acclimatized mix culture. Initial concentration of styrene and ethylbenzene in the liquid phase vacillated from 0 to 220 mg/l. The Andrew model was applied for the biodegradation of individual substrates and the estimated constants of the equation for styrene and ethylbenzene were μmax = 0.1581, 0.2090 (1/h), KS =25.91, 37.77 (mg/L), KI =13.15, 62.62 (mg/L), respectively. The accomplished parameters from single substrate degradation tests were used to predict possible interaction factors achieved from dual substrate experiments. The Sum Kinetics with Interaction Parameters (SKIP) model and the purely competitive enzyme kinetics model were employed to evaluate any interactions. The SKIP model was found to accurately describe these interactions. Moreover, it was revealed that ethylbenzene plays an influential role on styrene consumption (e.g. IE,S = 1.64) compared to styrene which has insignificant inhibitory effect on ethylbenzene usage (e.g. IS,E =0.4) . The active site differences for styrene and ethylbenzene biodegradation and the pathway variations for biodegradation are among the major potential reasons for failure of the estimation that occurred in purely competitive kinetics model. This study is the first to calculate the interactions between styrene and ethylbenzene.

Cellular automata-based modelling and simulation of biofilm structure on multi-core computers.

The article presents a mathematical model of biofilm growth for aerobic biodegradation of a toxic carbonaceous substrate. Modelling of biofilm growth has fundamental significance in numerous processes of biotechnology and mathematical modelling of bioreactors. The process following double-substrate kinetics with substrate inhibition proceeding in a biofilm has not been modelled so far by means of cellular automata. Each process in the model proposed, i.e. diffusion of substrates, uptake of substrates, growth and decay of microorganisms and biofilm detachment, is simulated in a discrete manner. It was shown that for flat biofilm of constant thickness, the results of the presented model agree with those of a continuous model. The primary outcome of the study was to propose a mathematical model of biofilm growth; however a considerable amount of focus was also placed on the development of efficient algorithms for its solution. Two parallel algorithms were created, differing in the way computations are distributed. Computer programs were created using OpenMP Application Programming Interface for C++ programming language. Simulations of biofilm growth were performed on three high-performance computers. Speed-up coefficients of computer programs were compared. Both algorithms enabled a significant reduction of computation time. It is important, inter alia, in modelling and simulation of bioreactor dynamics.

Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part A–Monocyclic and Polycyclic Aromatic Hydrocarbons

Present study focused on the screening of bacterial consortium for biodegradation of monocyclic aromatic hydrocarbon (MAH) and polycyclic aromatic hydrocarbons (PAHs). Target compounds in the present study were naphthalene, acenaphthene, phenanthrene (PAHs), and benzene (MAH). Microbial consortia enriched with the above target compounds were used in screening experiments. Naphthalene-enriched consortium was found to be the most efficient consortium, based on its substrate degradation rate and its ability to degrade other aromatic pollutants with significantly high efficiency. Substrate degradation rate with naphthalene-enriched culture followed the order benzene > naphthalene > acenaphthene > phenanthrene. Chryseobacterium and Rhodobacter were discerned as the predominant species in naphthalene-enriched culture. They are closely associated to the type strain Chryseobacterium arthrosphaerae and Rhodobacter maris, respectively. Single substrate biodegradation studies with naphthalene (PAH) and benzene (MAH) were carried out using naphthalene-enriched microbial consortium (NAPH). Phenol and 2-hydroxybenzaldehyde were identified as the predominant intermediates during benzene and naphthalene degradation, respectively. Biodegradation of toluene, ethyl benzene, xylene, phenol, and indole by NAPH was also investigated. Monod inhibition model was able to simulate biodegradation kinetics for benzene, whereas multiple substrate biodegradation model was able to simulate biodegradation kinetics for naphthalene.

Biodegradation of Various Aromatic Compounds by Enriched Bacterial Cultures: Part B--Nitrogen-, Sulfur-, and Oxygen-Containing Heterocyclic Aromatic Compounds.

Present study focused on the biodegradation of various heterocyclic nitrogen, sulfur, and oxygen (NSO) compounds using naphthalene-enriched culture. Target compounds in the study were pyridine, quinoline, benzothiophene, and benzofuran. Screening studies were carried out using different microbial consortia enriched with specific polycyclic aromatic hydrocarbon (PAH) and NSO compounds. Among different microbial consortia, naphthalene-enriched culture was the most efficient consortium based on high substrate degradation rate. Substrate degradation rate with naphthalene-enriched culture followed the order pyridine > quinoline > benzofuran > benzothiophene. Benzothiophene and benzofuran were found to be highly recalcitrant pollutants. Benzothiophene could not be biodegraded when concentration was above 50 mg/l. It was observed that 2-(1H)-quinolinone, benzothiophene-2-one, and benzofuran-2,3-dione were formed as metabolic intermediates during biodegradation of quinoline, benzothiophene, and benzofuran, respectively. Quinoline-N and pyridine-N were transformed into free ammonium ions during the biodegradation process. Biodegradation pathways for various NSO compounds are proposed. Monod inhibition model was able to simulate single substrate biodegradation kinetics satisfactorily. Benzothiophene and benzofuran biodegradation kinetics, in presence of acetone, was simulated using a generalized multi-substrate model.

Modeling the effect of soil meso- and macropores topology on the biodegradation of a soluble carbon substrate

Soil structure and interactions between biotic and abiotic processes are increasingly recognized as important for explaining the large uncertainties in the outputs of macroscopic SOM decomposition models. We present a numerical analysis to assess the role of meso- and macropore topology on the biodegradation of a soluble carbon substrate in variably water saturated and pure diffusion conditions . Our analysis was built as a complete factorial design and used a new 3D pore-scale model, LBioS, that couples a diffusion lattice-Boltzmann model and a compartmental biodegradation model. The scenarios combined contrasted modalities of four factors: meso- and macropore space geometry, water saturation, bacterial distribution and physiology. A global sensitivity analysis of these factors highlighted the role of physical factors in the biodegradation kinetics of our scenarios. Bacteria location explained 28% of the total variance in substrate concentration in all scenarios, while the interactions among location, saturation and geometry explained up to 51% of it.

Modeling and Simulation for Biodegradation of Mono-, Binary-, and Tertiary-substrate Batch Systems of Different Polyaromatic Sulfur Heterocyclic Compounds

Biodegradation kinetics of different polyaromatic sulfur heterocyclic compounds (PASHs): thiophene (Th), benzothiophene (BT), and dibenzothiophene (DBT) in a series of batch experiments were investigated as mono-, binary-, and tertiary-substrate systems to study the substrates interaction effect and capabilities of Bacillus sphaericus HN1 to utilize PASHs as sole carbon and energy source in mono- and multi-substrate systems. A multiple comparison test was performed for growth of microorganism and substrate biodegradation to obtain pairwise comparison between the three studied systems. Both tests ANOVA1 and Kruskal-Wallis showed that there was a highly statistically significant difference in growth of HN1 between negative control (free of PASHs) and all other treatments (p = 2.2105e-7 and 9.303e-4, respectively). Although, there was a statistically significant difference for biodegradation of DBT in mono– and binary-substrate systems within the time interval 96–168 h (p < 0.05), but there was a nonstatistically significant difference in the biodegradation of both Th and BT in the three studied systems (p > 0.05). A multi-substrate form of the Monod kinetic model was applied to predict the substrate interactions in binary- and tertiary-substrate systems using the Monod parameters derived from the mono-substrate systems. Simulation of the applied models to describe and estimate the biodegradation kinetics of the three studied PASHs in the different investigated systems was performed and the validity of the models was confirmed.

Kinetics of Substrate Biodegradation under the Cumulative Effects of Bioavailability and Self-Inhibition.

Microbial degradation is an important process in many environments controlling for instance the cycling of nutrients or the biodegradation of contaminants. At high substrate concentrations toxic effects may inhibit the degradation process. Bioavailability limitations of a degradable substrate can therefore either improve the overall dynamics of degradation by softening the contaminant toxicity effects to microorganisms, or slow down the biodegradation by reducing the microbial access to the substrate. Many studies on biodegradation kinetics of a self-inhibitive substrate have mainly focused on physiological responses of the bacteria to substrate concentration levels without considering the substrate bioavailability limitations rising from different geophysical and geochemical dynamics at pore-scale. In this regard, the role of bioavailability effects on the kinetics of self-inhibiting substrates is poorly understood. In this study, we theoretically analyze this role and assess the interactions between self-inhibition and mass transfer-limitations using analytical/numerical solutions, and show the findings practical relevance for a simple model scenario. Although individually self-inhibition and mass-transfer limitations negatively impact biodegradation, their combined effect may enhance biodegradation rates above a concentration threshold. To our knowledge, this is the first theoretical study describing the cumulative effects of the two mechanisms together.

Simultaneous biodegradation of bisphenol A and a biogenic substrate in semi-continuous activated sludge reactors.

In this work, the simultaneous degradation of BPA and cheese whey (CW) in semi-continuous activated sludge reactors was studied. The acclimation process and microbial growth on BPA, CW and BPA + CW were analyzed. In addition, the effect of increasing CW concentration on the BPA degradation by acclimated activated sludge was also studied. In order to reduce the factors involved in the analysis of the simultaneous degradation of BPA and CW, the effect of bisphenol A (BPA) on activated sludge not previously exposed to BPA (native activated sludge) was studied. Results demonstrate that BPA concentrations lower than 40 mg l(-1) had a negligible effect on the growth of native activated sludge. In the semi-continuous reactors, the presence of CW increased the acclimation time to 40 mg l(-1) of BPA. Once the capability of degrading BPA was acquired, the removal of BPA was not affected by the presence of CW. Increasing the CW concentration did not affect the removal of BPA by the acclimated activated sludge. Additionally, the CW consumption was not modified by the presence of BPA. Kinetic and stoichiometric coefficients reported in the present work can be useful in developing mathematical models to describe the simultaneous aerobic biodegradation of a biogenic substrate, such as CW, and BPA by activated sludge.

Biodegradation kinetics of benzene, toluene and xylene compounds: microbial growth and evaluation of models.

The biodegradation kinetics of BTX compounds (benzene, toluene, and xylene) individually and as mixtures was studied using models with different levels of sophistication. To compare the performance of the unstructured models applied in this work we used experimental data obtained here and some results published in the literature. The system description was based on the material balances of key components for batch operations, where the Monod and Andrews models were applied to predict the biodegradation of individual substrates. To simulate the biodegradation kinetics of substrate mixtures, models of substrate inhibition were applied along with the Sum Kinetics with Interaction Parameters (SKIP) models, where for two-component association toluene-xylene SKIP model presented better performance and for tri-component association benzene-toluene-xylene, the uncompetitive inhibition model was better. The kinetic parameters were estimated via a global search method known as Particle Swarm Optimization (PSO). The main result of this study is that the sophisticated biodegradation kinetics of BTX mixtures can be successfully described by applying the SKIP model, with the main advantage being the consideration of the substrate interactions.

Cultivation requirements and substrate degradation of the edible mushroom Gymnopilus pampeanus—A novel species for mushroom cultivation

The production of new species of edible mushrooms is an innovative way to recycle agro-industrial wastes into food production. The genus Gymnopilus has a large number of xylophagous species being Gymnopilus pampeanus the only consumed species. The objective of this work is to determine the optimal condition needed to cultivate G. pampeanus, to evaluate its biological efficiency and to determine the biodegradation of substrate. Populus and Eucalyptus sawdust were used as substrates for production. We determined that light is necessary for a normal development of primordia. Strain ICFC 748/12 produces the highest biological efficiency on Populus sawdust reaching a mean of 70.67%. G. pampeanus has a strong capacity to degrade Eucalyptus and Populus. This mushroom has the ability to decompose cellulose and also to decay lignin, thus being white rot fungi. This is the first report of the cultivation of this species on lignocellulosic waste which turns it into a promising species for commercial production.

Fate of injected CO2 in the Wilcox Group, Louisiana, Gulf Coast Basin: Chemical and isotopic tracers of microbial–brine–rock–CO2 interactions

The “2800’ sandstone” of the Olla oil field is an oil and gas-producing reservoir in a coal-bearing interval of the Paleocene–Eocene Wilcox Group in north-central Louisiana, USA. In the 1980s, this producing unit was flooded with CO2 in an enhanced oil recovery (EOR) project, leaving ∼30% of the injected CO2 in the 2800’ sandstone post-injection. This study utilizes isotopic and geochemical tracers from co-produced natural gas, oil and brine to determine the fate of the injected CO2, including the possibility of enhanced microbial conversion of CO2 to CH4 via methanogenesis. Stable carbon isotopes of CO2, CH4 and DIC, together with mol% CO2 show that 4 out of 17 wells sampled in the 2800’ sandstone are still producing injected CO2. The dominant fate of the injected CO2 appears to be dissolution in formation fluids and gas-phase trapping. There is some isotopic and geochemical evidence for enhanced microbial methanogenesis in 2 samples; however, the CO2 spread unevenly throughout the reservoir, and thus cannot explain the elevated indicators for methanogenesis observed across the entire field. Vertical migration out of the target 2800’ sandstone reservoir is also apparent in 3 samples located stratigraphically above the target sand. Reservoirs comparable to the 2800’ sandstone, located along a 90-km transect, were also sampled to investigate regional trends in gas composition, brine chemistry and microbial activity. Microbial methane, likely sourced from biodegradation of organic substrates within the formation, was found in all oil fields sampled, while indicators of methanogenesis (e.g. high alkalinity, δ13C-CO2 and δ13C-DIC values) and oxidation of propane were greatest in the Olla Field, likely due to its more ideal environmental conditions (i.e. suitable range of pH, temperature, salinity, sulfate and iron concentrations).

Biogas production using anaerobic groundwater containing a subterranean microbial community associated with the accretionary prism.

In a deep aquifer associated with an accretionary prism, significant methane (CH4) is produced by a subterranean microbial community. Here, we developed bioreactors for producing CH4 and hydrogen (H2) using anaerobic groundwater collected from the deep aquifer. To generate CH4, the anaerobic groundwater amended with organic substrates was incubated in the bioreactor. At first, H2 was detected and accumulated in the gas phase of the bioreactor. After the H2 decreased, rapid CH4 production was observed. Phylogenetic analysis targeting 16S rRNA genes revealed that the H2-producing fermentative bacterium and hydrogenotrophic methanogen were predominant in the reactor. The results suggested that syntrophic biodegradation of organic substrates by the H2-producing fermentative bacterium and the hydrogenotrophic methanogen contributed to the CH4 production. For H2 production, the anaerobic groundwater, amended with organic substrates and an inhibitor of methanogens (2-bromoethanesulfonate), was incubated in a bioreactor. After incubation for 24 h, H2 was detected from the gas phase of the bioreactor and accumulated. Bacterial 16S rRNA gene analysis suggested the dominance of the H2-producing fermentative bacterium in the reactor. Our study demonstrated a simple and rapid CH4 and H2 production utilizing anaerobic groundwater containing an active subterranean microbial community.