title: HRT dependent performance and bacterial community population of granular hydrogen-producing mixed cultures fed with galactose.
abstract: The effects of hydraulic retention times (HRTs-6, 3 and 2 h) on H2 production, operational stability and bacterial population response in a continuously stirred tank reactor (CSTR) were evaluated using galactose. A peak hydrogen production rate (HPR) of 25.9 L H2/L-d was obtained at a 3 h HRT with an organic loading rate (OLR) of 120 g/L-d, while the maximum hydrogen yield (HY) of 2.21 mol H2/mol galactose was obtained at a 6 h HRT (60 g galactose/L-d). Butyrate was dominant and the lactate concentration increased as HRT decreased, which significantly affected the HY. Biomass concentration (VSS) decreased from 16 to 3g/L at a 2 h HRT, leading to failure. A 3 h HRT supported the favorable growth of Clostridium species, as indicated by an increase in their populations from 25.4% to 27%, while significantly reducing Bacilli populations from 61.6% to 54.2%, indicating that this was the optimal condition.
authors: Sustainable Management of Natural Resources and Environment Research Group, Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Viet Nam; Department of Environmental Engineering, Daegu University, Gyeongsan, Gyeongbuk 712-714, South Korea.
authors: Gopalakrishnan
authors: G
authors: Kumar
authors: Department of Environmental Engineering, Daegu University, Gyeongsan, Gyeongbuk 712-714, South Korea.
authors: Periyasamy
authors: P
authors: Sivagurunathan
authors: Civil, Environmental and Architectural Engineering, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-714, South Korea; IT Convergence Materials R&D Group, Korea Institute of Industrial Technology, Chungnam 330-825, South Korea.
authors: Jeong-Hoon
authors: JH
authors: Park
authors: Department of Environmental Engineering, Daegu University, Gyeongsan, Gyeongbuk 712-714, South Korea; Civil, Environmental and Architectural Engineering, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-714, South Korea.
authors: Jong-Hun
authors: JH
authors: Park
authors: Civil, Environmental and Architectural Engineering, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-714, South Korea.
authors: Hee-Deung
authors: HD
authors: Park
authors: IT Convergence Materials R&D Group, Korea Institute of Industrial Technology, Chungnam 330-825, South Korea.
authors: Jeong-Jun
authors: JJ
authors: Yoon
authors: Department of Environmental Engineering, Daegu University, Gyeongsan, Gyeongbuk 712-714, South Korea. Electronic address: sanghkim1@daegu.ac.kr.
authors: Sang-Hyoun
authors: SH
authors: Kim
mesh_terms: D001419:Bacteria / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D056804:Biofuels; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D003013:Clostridium / Q000187:drug effects / Q000254:growth & development; D005285:Fermentation / Q000187:drug effects; D005690:Galactose / Q000494:pharmacology*; D006859:Hydrogen / Q000378:metabolism*; D010802:Phylogeny; D012995:Solubility; D013997:Time Factors
chemical_list: D056804:Biofuels; D006859:Hydrogen; D005690:Galactose
keywords: Butyrate; Galactose; Granular biomass; Hydraulic retention time; Lactate