Bacillus paraflexus sp. nov., isolated from compost

Abstract

A Gram-stain-positive, rod-shaped, endospore-forming, aerobic bacterium capable of growing at 15–42 °C (optimum 30 °C) and at pH 5–11 (optimum pH 7) was isolated from compost. Its taxonomic position was deduced using a polyphasic approach and the strain was designated RC2T. 16S rRNA gene sequence analysis showed that the isolate belongs to the division Firmicutes , forming a clade within the cluster containing Bacillus flexus IFO 15715T, and showed highest similarity to B. flexus IFO 15715T (98.1 %). The cell wall contained meso-diaminopimelic acid as the diagnostic diamino acid. The major cellular fatty acids of the novel strain were iso-C15:0 (36.83 %), anteiso-C15:0 (49.19 %) and C16:0 (5.19 %). DNA–DNA hybridization between strain RC2T and B. flexus DSM 1320T showed a level of relatedness of 54.5 %. The polar lipid profile of strain RC2T showed the presence of phosphatidylglycerol, diphosphatidylglycerol and phosphatidylethanolamine. The predominant isoprenoid quinone was MK-7 and the G+C content of strain RC2T was 37.6 mol%. On the basis of phenotypic characteristics, phylogenetic analysis and the results of biochemical and physiological tests, strain RC2T was clearly distinguished from closely related members of the genus, and the strain is assigned to a novel species, for which the name Bacillus paraflexus sp. nov. is proposed. The type strain is RC2T ( = MTCC 9831T = MCC 2100T = KCTC 13724T = CCM 7754T).