Bacillus nitroreducens sp. nov., a humus-reducing bacterium isolated from a compost.

Abstract

A Gram-staining-positive, facultative anaerobic, motile and rod-shaped bacterium, designated GSS08(T), was isolated from a windrow compost pile and characterized by means of a polyphasic approach. Growth occurred with 0-4% (w/v) NaCl (optimum 1%), at pH 6.5-9.5 (optimum pH 7.5) and at 20-45°C (optimum 37°C). Anaerobic growth occurred with anthraquinone-2,6-disulphonate, fumarate and NO3 (-) as electron acceptor. The main respiratory quinone was MK-7. The predominant polar lipids were diphosphatidylglycerol and phosphatidylethanolamine. The major fatty acids (>5%) were iso-C15:0 (43.1%), anteiso-C15:0 (27.4%) and iso-C16:0 (8.3%). The DNA G+C content was 39.6mol%. The phylogenetic analysis based on 16S rRNA gene sequences revealed that strain GSS08(T) formed a phyletic lineage with the type strain of Bacillus humi DSM 16318(T) with a high sequence similarity of 97.5%, but it displayed low sequence similarity with other valid species in the genus Bacillus (<96.0%). The DNA-DNA relatedness between strains GSS08(T) and B. humi DSM 16318(T) was 50.8%. The results of phenotypic, chemotaxonomic and genotypic analyses clearly indicated that strain GSS08(T) represents a novel species, for which the name Bacillus nitroreducens sp. nov. is proposed. The type strain is GSS08(T) (=KCTC 33699(T)=MCCC 1K01091(T)).