Previous Article | Next Article ![]()
Appl. Environ. Microbiol., 05 1997, 1732-1738, Vol 63, No. 5
B Kamlage, B Gruhl and M Blaut
Two gram-positive, strictly anoxic, coccoid- to rod-shaped strains of
bacteria, Clostridium coccoides 1410 and C. coccoides 3110, were isolated
from human feces on the typical homoacetogenic substrates formate plus H2
plus CO2 (strain 1410) and vanillate plus H2 plus CO2 (strain 3110) in the
presence of 2-bromoethanesulfonate to inhibit methanogenesis. On the basis
of 16S rRNA sequencing, DNA-DNA hybridization, and physiological and
morphological parameters, both isolates are closely related to C. coccoides
DSM 935T. The G+C contents of the DNA were 46.1 and 46.2 mol% for C.
coccoides 1410 and C. coccoides 3110, respectively. Cytochromes could not
be detected. Formate was degraded exclusively to acetate, whereas vanillate
was O- demethylated, resulting in acetate and 3,4-dihydroxybenzoate, the
latter being further decarboxylated to catechol. In the presence of organic
substrates, H2 was cometabolized to acetate, but both strains failed to
grow autotrophically. Lactose, lactulose, sorbitol, glucose, and various
other carbohydrates supported growth as well. Untypical of homoacetogens,
glucose and sorbitol were fermented not exclusively to acetate; instead,
considerable amounts of succinate and D-lactate were produced. H2 was
evolved from carbohydrates only in negligible traces. Acetogenesis from
formate plus H2 plus CO2 or vanillate plus H2 plus CO2 was constitutive,
whereas utilization of carbohydrates was inducible. Hydrogenase, CO
dehydrogenase, formate dehydrogenase, and all of the tetrahydrofolic
acid-dependent, C1 compound-converting enzymes of the acetyl-coenzyme A
pathway of homoacetogenesis were present in cell extracts.
Copyright © 1997, American Society for Microbiology
Isolation and characterization of two new homoacetogenic hydrogen- utilizing bacteria from the human intestinal tract that are closely related to Clostridium coccoides
German Institute of Human Nutrition (DIfE), Department of Gastrointestinal Microbiology, Potsdam-Rehbrucke, Germany. Bkam@ern.dife.d400.dc
This article has been cited by other articles:
| J. Bacteriol. | Microbiol. Mol. Biol. Rev. | Eukaryot. Cell | All ASM Journals |
|---|