title: Characterization of microbial compositions in a thermophilic chemostat of mixed culture fermentation.
abstract: The microbial community compositions of a chemostat enriched in a thermophilic (55 °C) mixed culture fermentation (MCF) for hydrogen production under different operational conditions were revealed in this work by integrating denaturing gradient gel electrophoresis (DGGE), Illumina Miseq high-throughput sequencing, and 16S rRNA clone library sequencing. The results showed that the community structure of the enriched cultures was relatively simple. Clones close to the genera of Thermoanaerobacter and/or Bacillus mainly dominated the bacteria. And homoacetogens and archaea were washed out and not detected even by Illumina Miseq high-throughput sequencing which supported the benefit for hydrogen production. On the other hand, the results revealed that the metabolic shift was clearly associated with the change of dominated bacterial groups. The effects of hydrogen partial pressure (PH2) and pH from 4.0 to 5.5 on the microbial compositions were not notable and Thermoanaerobacter was dominant, thus, the metabolites were also not changed. While Bacillus, Thermoanaerobacter and Propionispora hippei dominated the bacteria communities at neutral pH, or Bacillus and Thermoanaerobacter dominated at high influent glucose concentrations, consequently the main metabolites shifted to acetate, ethanol, propionate, or lactate. Thereby, the effect of microbial composition on the metabolite distribution and shift shall be considered when modeling thermophilic MCF in the future.
authors.affiliation: Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei, 066004, People's Republic of China. zhfang@ysu.edu.cn.|CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China. zhfang@ysu.edu.cn.
authors.forename: Fang
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei, 066004, People's Republic of China.
authors.forename: Jing-Hua
authors.initials: JH
authors.lastname: Yang
authors.affiliation: Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei, 066004, People's Republic of China.
authors.forename: Kun
authors.initials: K
authors.lastname: Dai
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei, 066004, People's Republic of China.
authors.forename: Qiu-Rong
authors.initials: QR
authors.lastname: Li
authors.affiliation: Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao, Hebei, 066004, People's Republic of China.
authors.forename: Fa-Ming
authors.initials: FM
authors.lastname: Gao
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China. rzeng@ustc.edu.cn.
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Zeng
mesh_terms: D001105:Archaea / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology*; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D006859:Hydrogen / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000378:metabolism; D064307:Microbiota; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D019344:Lactic Acid; D000431:Ethanol; D006859:Hydrogen
keywords: Chemostat; Clone library; Denaturing gradient gel electrophoresis; Illumina Miseq sequencing; Mixed culture fermentation; Thermophilic