title: Metabolic and energetic aspects of biohydrogen production of Clostridium tyrobutyricum: The effects of hydraulic retention time and peptone addition.
abstract: This study evaluates the microbial metabolism and energy demand in fermentative biohydrogen production using Clostridium tyrobutyricum FYa102 at different hydraulic retention times (HRT) over a period of 1-18 h. The hydrogen yield shows a positive correlation with the butyrate yield, the B/A ratio, and the Y(H2)/2(Y(HAc)+Y(HBu)) ratio, but a negative correlation with the lactate yield. A decrease in HRT, which is accompanied by an increased biomass growth, tends to decrease the B/A ratio, due presumably to a higher energy demand for microbial growth. The production of lactate at a low HRT, however, may involve an unfavorable change in e(-) equiv distribution to result in a reduced hydrogen production. Finally, the relatively high hydrogen yields observed in the bioreactor with the peptone addition may be ascribed to the utilization of peptone as an additional energy and/or amino-acid source, thus reducing the glucose demand for biomass growth during the hydrogen production process.
authors.affiliation: Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan. whang@mail.ncku.edu.tw
authors.forename: Liang-Ming
authors.initials: LM
authors.lastname: Whang
authors.forename: Che-An
authors.initials: CA
authors.lastname: Lin
authors.forename: I-Chun
authors.initials: IC
authors.lastname: Liu
authors.forename: Chao-Wei
authors.initials: CW
authors.lastname: Wu
authors.forename: Hai-Hsuan
authors.initials: HH
authors.lastname: Cheng
mesh_terms: D000085:Acetates / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000641:Ammonia / Q000494:pharmacology; D056804:Biofuels / Q000032:analysis*; D019149:Bioreactors / Q000382:microbiology; D002087:Butyrates / Q000378:metabolism; D048014:Clostridium tyrobutyricum / Q000187:drug effects* / Q000378:metabolism*; D004734:Energy Metabolism / Q000187:drug effects*; D005285:Fermentation / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D006859:Hydrogen / Q000378:metabolism*; D006865:Hydrogenation / Q000187:drug effects; D007773:Lactates / Q000378:metabolism; D010461:Peptones / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D000085:Acetates; D056804:Biofuels; D002087:Butyrates; D007773:Lactates; D010461:Peptones; D000641:Ammonia; D006859:Hydrogen; D000255:Adenosine Triphosphate; D005947:Glucose