title: Changes in performance and bacterial communities in response to various process disturbances in a high-rate biohydrogen reactor fed with galactose.
abstract: High-rate biohydrogen production was achieved via hybrid immobilized cells fed with galactose in a continuous reactor system. The hybrid immobilized cells were broken down after 20 days and began to form granules by self-aggregation. The peak hydrogen production rate (HPR) and hydrogen yield (HY) of 11.8 ± 0.6 LH2/L-d and 2.1 ± 0.1 mol H2/molgalactose(added), respectively, were achieved at the hydraulic retention time (HRT) of 8h with an organic loading rate (OLR) of 45 g/L-d. This is the highest yet reported for the employment of galactose in a continuous system. Various process disturbances including shock loading, acidification, alkalization and starvation were examined through bacterial community analysis via pyrosequencing of the 16S rRNA genes. The proportion of Clostridia increased during the stable biohydrogen production periods, while that of Bacilli increased when the reactor was disturbed. However, due to the stability of the self-aggregated granules, the process performance was regained within 4-7 days.
authors: School of Civil, Environmental and Architectural Engineering, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-714, South Korea.
authors: Jeong-Hoon
authors: JH
authors: Park
authors: 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: Jong-Hun
authors: JH
authors: Park
authors: School of Civil, Environmental and Architectural Engineering, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-714, South Korea.
authors: Hee-Deung
authors: HD
authors: Park
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: D000693:Anaerobiosis; D018533:Biomass; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods; D002244:Carbon / Q000737:chemistry; D018914:Cells, Immobilized; D003013:Clostridium / Q000378:metabolism*; D005285:Fermentation; D005690:Galactose / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009930:Organic Chemicals / Q000737:chemistry; D010802:Phylogeny; D020560:Proteobacteria / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000737:chemistry
chemical_list: D009930:Organic Chemicals; D012336:RNA, Ribosomal, 16S; D002244:Carbon; D006859:Hydrogen; D005690:Galactose
keywords: Biohydrogen; Hybrid immobilized cells; Process disturbance; Pyrosequencing; Self-aggregation