title: Isolation and characterization of a hydrogen- and ethanol-producing Clostridium sp. strain URNW.
abstract: Identification, characterization, and end-product synthesis patterns were analyzed in a newly identified mesophilic, anaerobic Clostridium sp. strain URNW, capable of producing hydrogen (H₂) and ethanol. Metabolic profiling was used to characterize putative end-product synthesis pathways of the Clostridium sp. strain URNW, which was found to grow on cellobiose; on hexose sugars, such as glucose, sucrose, and mannose; and on sugar alcohols, like mannitol and sorbitol. When grown in batch cultures on 2 g cellobiose·L⁻¹, Clostridium sp. strain URNW showed a cell generation time of 1.5 h, and the major end-products were H2, formate, carbon dioxide (CO₂), lactate, butyrate, acetate, pyruvate, and ethanol. The total volumetric H₂ production was 14.2 mmol·(L culture)⁻¹ and the total production of ethanol was 0.4 mmol·(L culture)⁻¹. The maximum yield of H₂ was 1.3 mol·(mol glucose equivalent)⁻¹ at a carbon recovery of 94%. The specific production rates of H₂, CO₂, and ethanol were 0.45, 0.13, and 0.003 mol·h⁻¹·(g dry cell mass)-1, respectively. BLAST analyses of 16S rDNA and chaperonin 60 (cpn60) sequences from Clostridium sp. strain URNW revealed a 98% nucleotide sequence identity with the 16S rDNA and cpn60 sequences from Clostridium intestinale ATCC 49213. Phylogenetic analyses placed Clostridium sp. strain URNW within the butyrate-synthesizing clostridia.
authors.affiliation: Department of Biosystems Engineering, University of Manitoba, Winnipeg, Canada.
authors.forename: Umesh
authors.initials: U
authors.lastname: Ramachandran
authors.forename: Nathan
authors.initials: N
authors.lastname: Wrana
authors.forename: Nazim
authors.initials: N
authors.lastname: Cicek
authors.forename: Richard
authors.initials: R
authors.lastname: Sparling
authors.forename: David B
authors.initials: DB
authors.lastname: Levin
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism; D002475:Cellobiose / Q000378:metabolism; D003013:Clostridium / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D003470:Culture Media; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D000431:Ethanol / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D003470:Culture Media; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D002245:Carbon Dioxide; D002475:Cellobiose; D000431:Ethanol; D006859:Hydrogen