Photosynthetic bacteria improved hydrogen yield of combined dark- and photo-fermentation

•Salt-tolerant dark and photo-fermentative bacterial consort was used in this study.•pH restriction effects H2 yield more than substrate restriction in dark fermentation.•Photosynthetic bacteria increase pH and H2 yield of combined dark- and photo-system.•Photosynthetic bacteria decrease ORP and VFA...

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Bibliographic Details
Published in:Journal of biotechnology 2019-08, Vol.302, p.18-25
Main Authors: Cai, Jinling, Zhao, Yaxuan, Fan, Jingbo, Li, Fengmei, Feng, Chenchen, Guan, Yue, Wang, Renyao, Tang, Na
Format: Article
Language:English
Subjects:
Bacteria - metabolism
Biohydrogen
Bioreactors - microbiology
Fermentation - physiology
Hydrogen - metabolism
Hydrogen-Ion Concentration
pH restriction
Products restriction
Saline water
Substrate restriction
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Summary:•Salt-tolerant dark and photo-fermentative bacterial consort was used in this study.•pH restriction effects H2 yield more than substrate restriction in dark fermentation.•Photosynthetic bacteria increase pH and H2 yield of combined dark- and photo-system.•Photosynthetic bacteria decrease ORP and VFAs of combined dark- and photo-system. Integration of dark- and photo-fermentation is a promising strategy to enhance saline wastewater treatment efficiency and biohydrogen production. In this study, dark- and photo-fermentative bacterial consortium was respectively enriched and their communities were analyzed using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Both consortia were mainly composed of hydrogen-producing strains. After the first-stage dark-fermentation, the following conditions were applied prior to the second-stage fermentation: fermentative broth pH regulation (the pH group), glucose addition (the glucose group), glucose addition and pH regulation (the glucose + pH group), photosynthetic bacteria addition (the photo group), and photosynthetic bacteria addition and pH regulation (the photo + pH group), respectively. Dark fermentative broth with no pretreatment was used as control (the control group). Then the second stage began. The results showed that pH restriction had more influence than substrate or products restriction on dark-fermentative hydrogen production. Addition of photo-fermentative bacteria after dark-fermentation increased the hydrogen yield (134%) and substrate utilization (67%). These findings indicated syntrophic interactions between dark- and photo-fermentative bacteria during the hydrogen production process.
ISSN:0168-1656
1873-4863
DOI:10.1016/j.jbiotec.2019.06.298