Isolation and characterization of a thermophilic sulfate-reducing bacterium, Desulfotomaculum thermosapovorans sp. nov.

Strain MLFT (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 Desulfotomaculum. 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 MLFT 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 MLFT and other thermophilic Desulfotomaculum species that also oxidize long-chain fatty acids. On the basis of our results, we propose that strain MLFT is a member of a new species, Desulfotomaculum thermosapovorans.