Changes in the microbial consortium during dark hydrogen fermentation in a bioelectrochemical system increases methane production during a two-stage process
Abstract Background Bioelectrochemical systems (BESs) are an innovative technology developed to influence conventional anaerobic digestion. We examined the feasibility of applying a BES to dark hydrogen fermentation and its effects on a two-stage fermentation process comprising hydrogen and methane...
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| Format: | Article |
| Language: | English |
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BMC
2018-06-01
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| Series: | Biotechnology for Biofuels |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s13068-018-1175-z |
| _version_ | 1818232881474961408 |
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| author | Kengo Sasaki Daisuke Sasaki Yota Tsuge Masahiko Morita Akihiko Kondo |
| author_facet | Kengo Sasaki Daisuke Sasaki Yota Tsuge Masahiko Morita Akihiko Kondo |
| author_sort | Kengo Sasaki |
| collection | DOAJ |
| description | Abstract Background Bioelectrochemical systems (BESs) are an innovative technology developed to influence conventional anaerobic digestion. We examined the feasibility of applying a BES to dark hydrogen fermentation and its effects on a two-stage fermentation process comprising hydrogen and methane production. The BES used low-cost, low-reactivity carbon sheets as the cathode and anode, and the cathodic potential was controlled at − 1.0 V (vs. Ag/AgCl) with a potentiostat. The operation used 10 g/L glucose as the major carbon source. Results The electric current density was low throughout (0.30–0.88 A/m2 per electrode corresponding to 0.5–1.5 mM/day of hydrogen production) and water electrolysis was prevented. At a hydraulic retention time of 2 days with a substrate pH of 6.5, the BES decreased gas production (hydrogen and carbon dioxide contents: 52.1 and 47.1%, respectively), compared to the non-bioelectrochemical system (NBES), although they had similar gas compositions. In addition, a methane fermenter (MF) was applied after the BES, which increased gas production (methane and carbon dioxide contents: 85.1 and 14.9%, respectively) compared to the case when the MF was applied after the NBES. Meta 16S rRNA sequencing revealed that the BES accelerated the growth of Ruminococcus sp. and Veillonellaceae sp. and decreased Clostridium sp. and Thermoanaerobacterium sp., resulting in increased propionate and ethanol generation and decreased butyrate generation; however, unknowingly, acetate generation was increased in the BES. Conclusions The altered redox potential in the BES likely transformed the structure of the microbial consortium and metabolic pattern to increase methane production and decrease carbon dioxide production in the two-stage process. This study showed the utility of the BES to act on the microbial consortium, resulting in improved gas production from carbohydrate compounds. |
| first_indexed | 2024-12-12T11:13:20Z |
| format | Article |
| id | doaj.art-038cd41956c14c299c8803769ac74a69 |
| institution | Directory Open Access Journal |
| issn | 1754-6834 |
| language | English |
| last_indexed | 2024-12-12T11:13:20Z |
| publishDate | 2018-06-01 |
| publisher | BMC |
| record_format | Article |
| series | Biotechnology for Biofuels |
| spelling | doaj.art-038cd41956c14c299c8803769ac74a692022-12-22T00:26:14ZengBMCBiotechnology for Biofuels1754-68342018-06-0111111210.1186/s13068-018-1175-zChanges in the microbial consortium during dark hydrogen fermentation in a bioelectrochemical system increases methane production during a two-stage processKengo Sasaki0Daisuke Sasaki1Yota Tsuge2Masahiko Morita3Akihiko Kondo4Graduate School of Science, Technology and Innovation, Kobe UniversityGraduate School of Science, Technology and Innovation, Kobe UniversityInstitute for Frontier Science Initiative, Kanazawa UniversityEnvironmental Chemistry Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power IndustryGraduate School of Science, Technology and Innovation, Kobe UniversityAbstract Background Bioelectrochemical systems (BESs) are an innovative technology developed to influence conventional anaerobic digestion. We examined the feasibility of applying a BES to dark hydrogen fermentation and its effects on a two-stage fermentation process comprising hydrogen and methane production. The BES used low-cost, low-reactivity carbon sheets as the cathode and anode, and the cathodic potential was controlled at − 1.0 V (vs. Ag/AgCl) with a potentiostat. The operation used 10 g/L glucose as the major carbon source. Results The electric current density was low throughout (0.30–0.88 A/m2 per electrode corresponding to 0.5–1.5 mM/day of hydrogen production) and water electrolysis was prevented. At a hydraulic retention time of 2 days with a substrate pH of 6.5, the BES decreased gas production (hydrogen and carbon dioxide contents: 52.1 and 47.1%, respectively), compared to the non-bioelectrochemical system (NBES), although they had similar gas compositions. In addition, a methane fermenter (MF) was applied after the BES, which increased gas production (methane and carbon dioxide contents: 85.1 and 14.9%, respectively) compared to the case when the MF was applied after the NBES. Meta 16S rRNA sequencing revealed that the BES accelerated the growth of Ruminococcus sp. and Veillonellaceae sp. and decreased Clostridium sp. and Thermoanaerobacterium sp., resulting in increased propionate and ethanol generation and decreased butyrate generation; however, unknowingly, acetate generation was increased in the BES. Conclusions The altered redox potential in the BES likely transformed the structure of the microbial consortium and metabolic pattern to increase methane production and decrease carbon dioxide production in the two-stage process. This study showed the utility of the BES to act on the microbial consortium, resulting in improved gas production from carbohydrate compounds.http://link.springer.com/article/10.1186/s13068-018-1175-zBioelectrochemical systemDark fermentationHydrogenMethaneMicrobial consortiumTwo-stage process |
| spellingShingle | Kengo Sasaki Daisuke Sasaki Yota Tsuge Masahiko Morita Akihiko Kondo Changes in the microbial consortium during dark hydrogen fermentation in a bioelectrochemical system increases methane production during a two-stage process Biotechnology for Biofuels Bioelectrochemical system Dark fermentation Hydrogen Methane Microbial consortium Two-stage process |
| title | Changes in the microbial consortium during dark hydrogen fermentation in a bioelectrochemical system increases methane production during a two-stage process |
| title_full | Changes in the microbial consortium during dark hydrogen fermentation in a bioelectrochemical system increases methane production during a two-stage process |
| title_fullStr | Changes in the microbial consortium during dark hydrogen fermentation in a bioelectrochemical system increases methane production during a two-stage process |
| title_full_unstemmed | Changes in the microbial consortium during dark hydrogen fermentation in a bioelectrochemical system increases methane production during a two-stage process |
| title_short | Changes in the microbial consortium during dark hydrogen fermentation in a bioelectrochemical system increases methane production during a two-stage process |
| title_sort | changes in the microbial consortium during dark hydrogen fermentation in a bioelectrochemical system increases methane production during a two stage process |
| topic | Bioelectrochemical system Dark fermentation Hydrogen Methane Microbial consortium Two-stage process |
| url | http://link.springer.com/article/10.1186/s13068-018-1175-z |
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