title: Effects of initial lactic acid concentration, HRTs, and OLRs on bio-hydrogen production from lactate-type fermentation.
abstract: A batch test and continuous operation were performed to identify the effect of lactate on hydrogen production at pH 4.5. When the initial lactic acid concentration was increased from 0 to 8 g/L in the batch test, the hydrogen yield also increased from 1.41 to 1.72 mol-H2/mol-glucose. The system exhibited a long lag time and an insignificant hydrogen yield with 16 g-lactic acid/L. A continuous stirred tank reactor (CSTR) was operated at different organic loading rates (OLRs: 10, 15, 20 and 40 g/L/day) and hydraulic retention times (HRTs: 6, 12 and 24 h). At an OLR of 20 g-glucose/L/day and 12 h of HRT, the hydrogen yield was 1.2 mol-H2/mol-glucose. The yield decreased with a 24 h HRT. Even though lactate was one of the major constituents of volatile fatty acids (VFAs), hydrogen production was feasible throughout the operation. Clostridium sp. was the dominant hydrogen-producing bacteria in the system.
authors.affiliation: Department of Environmental Science and Engineering, Center for Environmental Studies, Kyung Hee University, Seochon-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
authors.forename: Tae-Hyeong
authors.initials: TH
authors.lastname: Kim
authors.forename: Yunhee
authors.initials: Y
authors.lastname: Lee
authors.forename: Kwang-Hyeon
authors.initials: KH
authors.lastname: Chang
authors.forename: Sun-Jin
authors.initials: SJ
authors.lastname: Hwang
mesh_terms: D061249:Batch Cell Culture Techniques; D056804:Biofuels / Q000032:analysis*; D019149:Bioreactors; D005285:Fermentation / Q000187:drug effects*; D005947:Glucose / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism*; D017404:In Situ Hybridization, Fluorescence; D007700:Kinetics; D019344:Lactic Acid / Q000494:pharmacology*; D012995:Solubility; D013997:Time Factors
chemical_list: D056804:Biofuels; D019344:Lactic Acid; D006859:Hydrogen; D005947:Glucose