Mesophilic cellulolytic Clostridia from freshwater environments

Journal Article · Thu Sep 01 04:00:00 EDT 1983 · Appl. Environ. Microbiol.; (United States)

OSTI ID:6858433

Leschine, S B; Casale-Parola, E

Eight strains of obligately anaerobic, mesophilic, cellulolytic bacteria were isolated from mud of freshwater environments. The isolates (C strains) were rodshaped, gram negative, and formed terminal spherical to oval spores that swelled the sporangium. The guanine plus cytosine content of the DNA of the C strains ranged from 30.7 to 33.2 mol% (midpoint of thermal denaturation). The C strains fermented cellulose with formation primarily of acetate, ethanol, CO/sub 2/, and H/sub 2/. Reducing sugars accumulated in the supernatant fluid of cultures which initially contained 0.4% (wt/vol) or more cellulose. The C strains resembled Clostridium cellobioparum in some phenotypic characteristics and Clostridium papyrosolvens in others, but they were not identical to either of these species. The C strains differed from thermophilic cellulolytic clostridia (e.g., Clostridium thermocellum) not only in growth temperature range but also because they fermented xylan and five-carbon products of plant polysaccharide hydrolysis such as D-xylose and L-arabinose. At 40 degrees C, cellulose was degraded by cellulolytic mesophilic cells (strain C7) at a rate comparable to that at which C. thermocellum degrades cellulose at 60 degrees C. Substrate utilization and growth temperature data indicated that the C strains contribute to the anaerobic breakdown of plant polymers in the environments they inhabit. 31 references.

• Research Organization: Univ. of Massachusetts, Amherst
• OSTI ID: 6858433
• Journal Information: Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 46:3; ISSN AEMID
• Country of Publication: United States
• Language: English

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ACETATES
ALCOHOLS
AQUATIC ECOSYSTEMS
BACTERIA
BIOCONVERSION
BIOPHOTOLYSIS
CARBOHYDRATES
CARBON COMPOUNDS
CARBON DIOXIDE
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CHALCOGENIDES
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ECOSYSTEMS
ENZYME ACTIVITY
ETHANOL
FERMENTATION
GROWTH
HYDROGEN PRODUCTION
HYDROXY COMPOUNDS
MESOPHILIC CONDITIONS
MICROORGANISMS
MORPHOLOGY
NUTRIENTS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
POLYSACCHARIDES
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SACCHARIDES
SUBSTRATES