ISOLATION AND CHARACTERIZATION OF A THERMOPHILIC SULFATE-REDUCING BACTERIUM, DESULFOTOMACULUM THERMOSAPOVORANS SP-NOV

Strain MLF(T) (T = type strain), a new thermophilic, spore-forming sulfate-reducing bacterium, was characterized and was found to be phenotypically, genotypically, and phylogenetically related to the genus Desul-fotomaculum. This organism was isolated from a butyrate enrichment culture that had been inoculated with a mixed compost containing rice hulls and peanut shells. The optimum temperature for growth was 50 degrees C. The G+C content of the DNA was 51.2 mol%. Strain MLF(T) incompletely oxidized pyruvate, butyrate, and butanol to acetate and presumably CO2. It used long chain fatty acids and propanediols. We observed phenotypic and phylogenetic differences between strain MLF(T) and other thermophilic Desulfotomaculum species that also oxidize long-chain fatty acids. On the basis of our results, we propose that strain MLF(T) is a member of a new species, Desulfotomaculum thermosapovorans.