Isolation and characterization of Desulfovibrio dechloracetivorans sp nov., a marine dechlorinating bacterium growing by coupling the oxidation of acetate to the reductive dechlorination of 2-chlorophenol

Strain SF3, a gram-negative, anaerobic, motile, short curved rod that grows by coupling the reductive dechlorination of 2-chlorophenol (2-CP) to the oxidation of acetate, was isolated from San Francisco Bay sediment, Strain SF3 grew at concentrations of NaCl ranging from 0.16 to 2.5%, but concentrations of KCI above 0.32% inhibited growth. The isolate used acetate, fumarate, lactate, propionate, pyruvate, alanine, and ethanol as electron donors for growth coupled to reductive dechlorination, Among the halogenated aromatic compounds tested, only the ortho position of chlorophenols was reductively dechlorinated, and additional chlorines at other positions blocked ortho dechlorination, Sulfate, sulfite, thiosulfate. and nitrate were also used as electron accepters for growth, The optimal temperature for growth was 30 degrees C, and no growth or dechlorination activity was observed at 37 degrees C. Growth by reductive dechlorination was revealed by a growth yield of about 1 g of protein per mel of 2-CP dechlorinated, and about 2.7 g of protein per mole of 2,6-dichlorophenol dechlorinated, The physiological features and 16S ribosomal DNA sequence suggest that the organism is a novel species of the genus Desulfovibrio and which we have designated Desulfovibrio dechloracetivorans, The unusual physiological feature of this strain is that it uses acetate as an electron donor and carbon source for growth with 2-CP but not with sulfate.