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 o xidation of acetate, was isolated from San Francisco Bay sediment, Strain S F3 grew at concentrations of NaCl ranging from 0.16 to 2.5%, but concentrat ions of KCI above 0.32% inhibited growth. The isolate used acetate, fumarat e, lactate, propionate, pyruvate, alanine, and ethanol as electron donors f or growth coupled to reductive dechlorination, Among the halogenated aromat ic compounds tested, only the ortho position of chlorophenols was reductive ly 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 deg rees C. Growth by reductive dechlorination was revealed by a growth yield o f about 1 g of protein per mel of 2-CP dechlorinated, and about 2.7 g of pr otein per mole of 2,6-dichlorophenol dechlorinated, The physiological featu res and 16S ribosomal DNA sequence suggest that the organism is a novel spe cies of the genus Desulfovibrio and which we have designated Desulfovibrio dechloracetivorans, The unusual physiological feature of this strain is tha t it uses acetate as an electron donor and carbon source for growth with 2- CP but not with sulfate.