Desulfoprunum benzoelyticum gen. nov., sp. nov., a Gram-stain-negative, benzoate-degrading, sulfate-reducing bacterium isolated from a wastewater treatment plant

A strictly anaerobic, mesophilic, sulfate-reducing bacterium, strain KoBa311(T), isolated from the wastewater treatment plant at Konstanz, Germany, was characterized phenotypically and phylogenetically. Cells were Gram-stain-negative, non-motile, oval to short rods, 3-5 µm long and 0.8-1.0 µm wide with rounded ends, dividing by binary fission and occurring singly or in pairs. The strain grew optimally in freshwater medium and the optimum temperature was 30 °C. Strain KoBa311(T) showed optimum growth at pH 7.3-7.6. Organic electron donors were oxidized completely to carbon dioxide concomitant with sulfate reduction to sulfide. At excess substrate supply, substrates were oxidized incompletely and acetate (mainly) and/or propionate accumulated. The strain utilized short-chain fatty acids, alcohols (except methanol) and benzoate. Sulfate and DMSO were used as terminal electron acceptors for growth. The genomic DNA G+C content was 52.3 mol% and the respiratory quinone was menaquinone MK-5 (V-H2). The major fatty acids were C16:0, C16:1ω7c/ω6c and C18:1ω7c. Phylogenetic analysis based on 16S rRNA gene sequences placed strain KoBa311(T) within the family Desulfobulbaceae in the class Deltaproteobacteria. Its closest related bacterial species on the basis of the distance matrix were Desulfobacterium catecholicum DSM 3882(T) (93.0% similarity), Desulfocapsa thiozymogenes (93.1%), Desulforhopalus singaporensis (92.9%), Desulfopila aestuarii (92.4%), Desulfopila inferna JS_SRB250Lac(T) (92.3%) and Desulfofustis glycolicus (92.3%). On the basis of phylogenetic, physiological and chemotaxonomic characteristics, strain KoBa311(T) was distinct from any related type species. Therefore, strain KoBa311(T) is considered to represent a novel species of a new genus, for which the name Desulfoprunum benzoelyticum gen. nov., sp. nov. is proposed. The type strain of Desulfoprunum benzoelyticum is KoBa311(T) ( =DSM 28570(T) =KCTC 15441(T)).