title: Predominance of cluster I Clostridium in hydrogen fermentation of galactose seeded with various heat-treated anaerobic sludges.
abstract: To identify the key bacterial populations in hydrogen fermentation of galactose, a fermentor seeded with a heat-treated sludge was operated. After 27h of fermentation, the proportion of butyric acid increased to 69.4wt.% and the gas production yield reached 1.0molH2/molgalactose. In the pyrosequencing of 16S rDNA, an increase of the proportion of the phylum Firmicutes from 4.2% to 92% (mostly cluster I Clostridium) was observed. To verify the predominance and the ubiquity of the cluster, five fermentors seeded with different heat-treated anaerobic sludges having different feedstock compositions and digestion temperatures were investigated using qPCR analyses. The abundance of the cluster increased >100-fold during the fermentation, regardless of the inocula. Moreover, the abundance was negatively correlated with the lag time of hydrogen production and positively correlated with the hydrogen production rate, demonstrating the relevance of the cluster to hydrogen production. Taken together, the results clearly revealed the importance of cluster I Clostridium in the hydrogen fermentation of galactose.
authors.affiliation: School of Civil, Environmental and Architectural Engineering, Korea University, Seoul 136-714, South Korea; IT Convergence Materials R&D Group, Korea Institute of Industrial Technology, Chungnam 330-825, South Korea.
authors.forename: Jeong-Hoon
authors.initials: JH
authors.lastname: Park
authors.affiliation: School of Civil, Environmental and Architectural Engineering, Korea University, Seoul 136-714, South Korea.
authors.forename: Sang-Hoon
authors.initials: SH
authors.lastname: Lee
authors.affiliation: IT Convergence Materials R&D Group, Korea Institute of Industrial Technology, Chungnam 330-825, South Korea.
authors.forename: Jeong-Jun
authors.initials: JJ
authors.lastname: Yoon
authors.affiliation: Department of Environmental Engineering, Daegu University, Gyeongbuk 712-714, South Korea.
authors.forename: Sang-Hyoun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: School of Civil, Environmental and Architectural Engineering, Korea University, Seoul 136-714, South Korea. Electronic address: heedeung@korea.ac.kr.
authors.forename: Hee-Deung
authors.initials: HD
authors.lastname: Park
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors / Q000382:microbiology; D003013:Clostridium / Q000235:genetics / Q000378:metabolism*; D004275:DNA, Ribosomal / Q000235:genetics; D005285:Fermentation; D005690:Galactose / Q000378:metabolism*; D006358:Hot Temperature; D006859:Hydrogen / Q000378:metabolism*; D016014:Linear Models; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000382:microbiology*
chemical_list: D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D006859:Hydrogen; D005690:Galactose
keywords: Biohydrogen; Clostridium; Galactose; Marine red algae; Pyrosequencing