Bacillus oryzaecorticis sp. nov., a moderately halophilic bacterium isolated from rice husks

Abstract

A Gram-stain-positive, aerobic, endospore-forming, moderately halophilic rod, designated strain R1(T), was isolated from rice husks and subjected to a taxonomic study using a polyphasic approach. Strain R1(T) produced spherical or ellipsoidal endospores at a subterminal position in swollen sporangia, and was catalase- and oxidase-positive. The isolate grew optimally at 37 °C and pH 6.0-7.0, and could grow in the presence of up to 9% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain R1(T) belongs to the genus Bacillus. The closest relatives of strain R1(T) were Bacillus subtilis subsp. subtilis NCIB 3610(T), Bacillus aquimaris TF-12(T), and Bacillus marisflavi TF-11(T), with 16S rRNA gene sequence similarities of 96.0%, 98.4%, and 98.7%, respectively. DNA-DNA relatedness values between the isolate and the reference strains were ≤42±3%. The predominant menaquinones were MK-5 (50%) and MK-7 (50%). The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, and phosphatidylethanolamine. The major cellular fatty acids were iso-C(15 : 0) (48.6%) and anteiso-C(15 : 0) (20.6%), and the cell-wall diamino acid was meso-diaminopimelic acid. On the basis of 16S rRNA gene sequence analyses and chemotaxonomic and phenotypic characteristics, it is concluded that strain R1(T) represents a novel species of the genus Bacillus, for which we propose the name Bacillus oryzaecorticis sp. nov. The type strain is R1(T) ( = KACC 17217(T) = KCCM 90231(T) = JCM 19602(T)).