Improved cellulose conversion to bio-hydrogen with thermophilic bacteria and characterization of microbial community in continuous bioreactor

Isotopic studies have shown that many of the world’s coalbed natural gas plays are secondary biogenic in origin, suggesting a potential for gas regeneration through enhanced microbial activities. The generation of biogas through biostimulation and bioaugmentation is limited to the bioavailability of coal-derived compounds and is considered carbon positive. Here we show that plant-derived carbohydrates can be used as alternative substrates for gas generation by the indigenous coal seam microorganisms. The results suggest that coalbeds can act as natural geobioreactors to produce low carbon renewable natural gas, which can be considered carbon neutral, or perhaps even carbon negative depending on the amount of carbon sequestered within the coal. In addition, coal bioavailability is no longer a limiting factor. This approach has the potential of bridging the gap between fossil fuels and renewable energy by utilizing existing coalbed natural gas infrastructure to produce low carbon renewable natural gas and reducing global warming.

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“…Pedobacter spp. are known to be dominant in the anaerobic hydrolysis of cellulose to produce bio-hydrogen 38 . Rhodopseudomonas spp.…”

Section: Resultsmentioning

confidence: 99%

Low carbon renewable natural gas production from coalbeds and implications for carbon capture and storage

et al. 2017

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“…Thus a great deal of attention is being paid to the use of biofuels from biomass as alternative and clean fuels. Hydrogen is considered a promising fuel source with high energy density and clean energy with only water generation after combustion . Petroleum refineries are the largest producers of hydrogen .…”

Section: Introductionmentioning

confidence: 99%

Effect of fermentation temperature on hydrogen production from xylose and the succession of hydrogen‐producing microflora

Qiu

Yuan

Sun

et al. 2017

J of Chemical Tech & Biotech

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BACKGROUND Hydrogen production through anaerobic dark fermentation is considered to be a potential biological process for xylose utilization. Temperature is one of the most important environmental factors, however, most studies have been carried out over a small temperature range. Batch tests were carried out to investigate the temperature effect on hydrogen production from xylose using a mixed culture over a wide temperature range (35–65°C). Hydrogen production, metabolite distribution and dynamics of microbial communities were investigated. RESULTS Hydrogen‐producing cultures were successfully enriched at each tested temperature. Two peaks of fermentation temperature for hydrogen production were observed at 35 and 55°C (1.11 and 1.30 mol‐H2 mol−1‐xyloseconsumed, respectively). Butyrate and acetate were the major liquid metabolites at 35–60°C. While at 65°C the main by‐product was ethanol. Polymerase chain reaction‐denaturing gradient gel electrophoresis (PCR‐DGGE) analysis indicated that Clostridium species were dominant at 35–40°C, while Thermoanaerobacterium dominated at 45–60°C. Both species were found at 65°C, but with lowest microbial community diversity. CONCLUSION Hydrogen production efficiency was mainly affected by the liquid metabolite distributions, which depended mainly upon the temperature. Several microbial community structures were formed at mesophilic, transition, thermophilic and extreme‐thermophilic conditions, resulting in different metabolic pathways of xylose and hydrogen production capacity. © 2017 Society of Chemical Industry

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“…A similar trend was observed when cellulose was used as the substrate (Figure 1B): heat-shock preconditioning gave a degree of acidi cation of 26 ± 1%, while alkali and acid conditioning methods gave acidi cation values of 22 ± 1% and 12 ± 1%, respectively. A lower degree of acidi cation was obtained with cellulose than with glucose because it is a more complex substrate than glucose, and its hydrolysis by anaerobic micro ora is more di cult [33].…”

Section: Comparison Of the Effect Of The Inoculum Conditioning Methods On Vfa Bioconversion And H 2 Productionmentioning

confidence: 99%

Towards PHA Production from Wastes: The Bioconversion Potential of Different Activated Sludge and Food Industry Wastes into VFAs Through Acidogenic Fermentation

Montiel-Jarillo

Gea

Artola

et al. 2021

Waste Biomass Valor

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Acidogenic fermentation of wastes produces volatile fatty acid (VFA)-rich streams that can be used as low-cost carbon sources for polyhydroxyalkanoate (PHA) production. In this study, an inoculum collected from an anaerobic reactor of a municipal WWTP was conditioned to suppress methanogenic activity. The heat-shock conditioning method of the inoculum proved to be more e cient than acid and alkaline conditioning methods for methanogen inhibition. Then, the pre-conditioned inoculum was used to determine the acidogenic potential of different wastes: three waste activated sludge (WAS) samples generated at different sludge retention times (SRTs, 2, 7 and 14 days), olive mill wastewater (OMW), glycerol, apple pomace (AP) and winterization oil cake (WOC). Batch tests were performed in quintuplicate at 37°C and pH 7. A higher degree of acidi cation was observed for high-rate activated sludge (2 days of SRT) (69%), followed by olive mill wastewater (OMW) (43%), while the lowest was for glycerol (16%). The results for the winterization oil cake (WOC) samples interestingly elucidated a high content of propionic acid with a high odd-to-even ratio (0.86) after fermentation. Feeding the VFA pro le obtained from WOC into a PHA production system led to a signi cant production of 0.64 g PHA g − 1 C with 30% polyhydrobutyrate (PHB) to 69% polyhydroxyvalerate (PHV) as monomeric units of HB-co-HV, decoupling the need for a related carbon source for co-polymer production. Statement Of NoveltyThe acidogenic potential of several industrial wastes was assessed with the context of being used as potential precursors for polyhydroxyalkanoate production by evaluating the odd-to-even ratio of the generated volatile fatty acids (VFA) pro le. To the best of our knowledge, this is the rst time high-rate WAS (2 days of SRT), WOC and AP were fermented with this ultimate objective. The VFA pro le obtained from WOC fermentation presented a high odd-to-even ratio (1.2 to 1.3). This mixture was fed into a PHA production system, yielding 0.64 g PHA g − 1 C with a composition of 30% PHB to 70% PHV. This mitigates the need for extra carbon sources to adjust the acetic acid to propionic acid proportion for co-polymer production. HighlightsInoculum heat shock provided the best acidogenic conditions High-rate activated sludge shows a high acidi cation potential Winterization oil cake bioconversion led to an odd-to-even ratio close to one An odd-to-even VFA ratio of 1.2 led to a 70% PHV proportion in the produced PHA.

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Improved cellulose conversion to bio-hydrogen with thermophilic bacteria and characterization of microbial community in continuous bioreactor

Cited by 28 publications

References 38 publications

Low carbon renewable natural gas production from coalbeds and implications for carbon capture and storage

Low carbon renewable natural gas production from coalbeds and implications for carbon capture and storage

Effect of fermentation temperature on hydrogen production from xylose and the succession of hydrogen‐producing microflora

Towards PHA Production from Wastes: The Bioconversion Potential of Different Activated Sludge and Food Industry Wastes into VFAs Through Acidogenic Fermentation

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