Draft Genome Sequence of Clostridium ultunense Strain Esp, a Syntrophic Acetate-Oxidizing Bacterium. Clostridium ultunense strain Esp belongs to the functional group of syntrophic acetate-oxidizing bacteria (SAOB), which have been identified as key organisms for efficient biogas production from protein-rich materials. Genome analysis and comparative genomics might aid us to define physiological features that are essential for maintaining this particular syntrophic lifestyle.

A syntrophic acetate-oxidizing bacterium, strain ESP was isolated from a previously described mesophilic triculture that was able to syntrophically oxidize acetate and form methane in stoichiometric amounts. Strain EST was isolated with substrates typically utilized by homoacetogenic bacteria. Strain ESP was a spore-forming, gram-positive, rod-shaped organism which utilized formate, glucose, ethylene glycol, cysteine, betaine, and pyruvate. Acetate and sometimes formate were the main fermentation products. Small amounts of alanine were also produced from glucose, betaine, and cysteine. Strain ESP grew optimally at 37 degrees C and pH 7. The G+C content of the DNA of strain BST was 32 mol%. A 16S rRNA sequence analysis revealed that strain ESP was a member of a new species of the genus Clostridium.