Bacillus miscanthi sp. nov., a alkaliphilic bacterium from the rhizosphere of Miscanthus sacchariflorus

Abstract

A novel bacterial strain, designated AK13(T) (=KACC 21401(T)=DSM 109981(T)), was isolated from the rhizosphere of Miscanthus sacchariflorus. Strain AK13(T) was found to be an aerobic, Gram-stain-positive, endospore-forming and rod-shaped bacterium. It formed yellow circular colonies with smooth convex surfaces. The genomic DNA G+C content of strain AK13(T) was estimated to be 40 mol%. Phylogenetic analysis based on 165 rRNA gene sequence similarity showed that this strain was most closely related to Bacillus lehensis MLB2T (99.4 %), Bacillus oshimensis K11(T) (98.8 %) and Bacillus patagoniensis PAT 0(T) (96.6 %). The average nucleotide identity values between strain AK13T and B. lehensis MLB2T, B. oshimensis K11(T) and B. patagoniensis PAT 05(T) were 90.93, 91.05 and 71.87 %, respectively, with the digital DNA-DNA hybridization values of 42.7, 42.6 and 18.8 %, respectively. Cells grew at 5-40 degrees C (optimum, 28-35 degrees C), pH 6.5-13 (optimum, pH 8-9) and in the presence of 0-13.0 % (w/v) NaCl (optimum, 1 %). The cell wall of strain AK13(T) contained meso-diaminopimelic acid, and the major isoprenoid quinone was MK-7. Results of fatty acid methyl ester analysis revealed that was the predominant cellular fatty acid. Two-dimensional thinlayer chromatography analysis indicated that the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and glycolipid. The genotypic and phenotypic characteristics suggested that strain AK13(T) represented a novel species of the genus Bacillus, and thus the name Bacillus miscanthi sp. nov. is proposed.