Characterization of a symbiotic coculture of Clostridium thermohydrosulfuricum YM3 and clostridium thermocellum YM4
- National Food Research Institute, Tsukuba (Japan)
Clostridium thermohydrosulfuricum YM3 and C. thermocellum YM4 were isolated from a coculture which was obtained from an enrichment culture inoculated with volcanic soil in Izu Peninsula, Japan. Strain YM3 had advantages over reported C. thermohydrosulfuricum strains in that it fermented inulin and could accumulate ethanol up to 1.3% (wt/vol). The highest ethanol yield obtained was 1.96 mol/mol of anhydroglucose unit in cellobiose. Strain YM4 had features different from those reported in C. thermocellum strains: it formed spores rarely (at a frequency of <10{sup {minus}5}), it required CO{sub 2} and Na{sub 2}CO{sub 3} for growth, and it fermented sucrose. Strain YM4 completely decomposed 1% Avicel within 25 h when the inoculum constituted 2 % of the culture medium volume, and it produced 0.22 U of Avicelase and 2.21 U of carboxymethylcellulase per ml of the medium. The doubling times on Avicel, cellobiose, and glucose were 2.7, 1.1, and 1.6 h, respectively. Reconstructed cocultures of strains YM3 and YM4 were very stable and degraded Avicel more rapidly than did strain YM4 monoculture. Without yeast extract, neither microorganism was able to grow. However, the coculture grew on cellulose without yeast extract and produced ethanol in high yield. Moreover, cell-free spent culture broth of strain YM3 could replace yeast extract in supporting the growth of strain YM4. The symbiotic relationship of the two bacteria in cellulose fermentation is probably a case of mutualism.
- OSTI ID:
- 6855046
- Journal Information:
- Applied and Environmental Microbiology; (USA), Vol. 56:1; ISSN 0099-2240
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CELLULOSE
FERMENTATION
CLOSTRIDIUM
PRODUCTIVITY
ETHANOL
BIOSYNTHESIS
CELLOBIOSE
CLOSTRIDIUM THERMOCELLUM
GLUCOSE
INULIN
METABOLISM
SACCHAROSE
SYMBIOSIS
ALCOHOLS
ALDEHYDES
BACTERIA
BIOCONVERSION
CARBOHYDRATES
DISACCHARIDES
HEXOSES
HYDROXY COMPOUNDS
MICROORGANISMS
MONOSACCHARIDES
OLIGOSACCHARIDES
ORGANIC COMPOUNDS
POLYSACCHARIDES
SACCHARIDES
SYNTHESIS
090900* - Biomass Fuels- Processing- (1990-)