Desulfomonile limimaris sp nov., an anaerobic dehalogenating bacterium from marine sediments

Strains DCB-M-T and DCB-F were isolated from anaerobic 3-chlorobenzeate (3C B)-mineralizing cultures enriched from marine sediments. The isolates are l arge, Gram-negative rods with a collar girdling each cell. The isolates are obligate anaerobes capable of reductive dechlorination of 3CB to benzoate. Growth by chlororespiration in strain DCB-M-T yielded 1.7 g protein mol(-1 ) 3CB dechlorinated with lactate as the electron donor. Strain DCB-M-T also used fumarate, sulfate, sulfite, thiosulfate and nitrate as physiological electron accepters for growth, but grew poorly on sulfate and nitrate. Redu ctive dechlorination was inhibited completely by sulfite and thiosulfate bu t not by sulfate. Both strains were incapable of growth at NaCl concentrati ons below 0.32% (w/v). They grew well at sea-water salt concentrations; how ever, the optimum growth rate was achieved at a NaCl concentration half tha t of sea water. The 16S rDNA sequence analysis shows strains DCB-M-T and DC B-F to be 99% similar to each other and 93 % similar to their closest relat ive, Desulfomonile tiedjei strain DCB-1(T). Strain DCB-M-T can also be dist inguished from strain DCB-1(T) by its inability to use acetate for growth o n 3CB and by its requirement for NaCl. The morphology, physiology and 165 r DNA sequences of DCB-M-T and DCB-F suggest that these strains represent a n ew, marine-adapted species of the genus Desulfomonile, designated Desulfomo nile limimaris sp. nov. The type strain is strain DCB-M-T (= ATCC 700979(T) ).