DESULFORHABDUS AMNIGENUS GEN-NOV SP-NOV, A SULFATE REDUCER ISOLATED FROM ANAEROBIC GRANULAR SLUDGE

From granular sludge of an upflow anaerobic sludge bed (UASB) reactor treating paper-mill wastewater, a sulfate-reducing bacterium (strain ASRB1) was isolated with acetate as sole carbon and energy source. The bacterium was rod-shaped, (1.4-1.9 x 2.5-3.4 mu m), nonmotile, and gram-negative. Optimum growth with acetate occurred around 37 degrees C in freshwater medium (doubling time: 3.5-5.0 days). The bacterium grew on a range of organic acids, such as acetate, propionate, and butyrate, and on alcohols, and grew autotrophically with H-2, CO2, and sulfate. Fastest growth occurred with formate, propionate, and ethanol (doubling time: approx. 1.5 days). Strain ASRB1 clusters with the delta subdivision of Proteobacteria and is closely related to Syntrophobacter wolinii, a syntrophic propionate oxidizer. Strain ASRB1 was characterized as a new genus and species: Desulforhabdus amnigenus.