A Desulfitobacterium strain isolated from human feces that does not dechlorinate chloroethenes or chlorophenols

An anaerobic bacterium, strain DP7, was isolated from human feces in minera l medium with formate and 0.02% yeast extract as energy and carbon source. This rod-shaped motile bacterium used pyruvate, lactate, formate, hydrogen, butyrate, and ethanol as electron donor for sulfite reduction. Other elect ron accepters such as thiosulfate, nitrate and fumarate stimulated growth i n the presence of 0.02% yeast extract and formate. Acetate was the only pro duct during fermentative growth on pyruvate. Six mol of pyruvate were ferme nted to 7 mol of acetate. C-13-NMR labeling experiments showed homoacetogen ic C-13-CO2 incorporation into acetate. The pH and temperature optimum of f ermentative growth on pyruvate was 7.4 and 37 degreesC, respectively. The g rowth rate under these conditions was approximately 0.10 h(-1). Strain DP7 was identified as a new strain of Desulfitobacterium frappieri on the basis of 16S rRNA sequence analysis (99% similarity) and DNA-DNA hybridization ( reassociation value of 83%) with Desulfitobacterium frappieri TCE1. In cont rast to described Desulfitobacterium strains, the newly isolated strain has not been isolated from a polluted environment and did not use chloroethene s or chlorophenols as electron acceptor.