Lentibacillus songyuanensis sp. nov., A Drought- and Salt- Tolerant Bacterium with Ability to Degrade Aniline Blue Isolated from Saline-Alkali Soil.

A Gram-stain-positive, aerobic and drought- and salt-resistant bacterium, designated as N15, was isolated from a saline-alkali soil in Songyuan city, Jilin Province, China. The strain grew in the presence of 0-12% (w/v) NaCl, at pH 6.0-8.0 and 15-42 °C; optimum growth was observed with 6.0% (w/v) NaCl, at pH 7.0 and 30 °C. Strain N15 tolerated up to 45% PEG6000 and 12% NaCl, and could efficiently degrade aniline blue. Phylogenetic analysis based on 16S rRNA genes placed strain N15 within genus Lentibacillus, forming a subclade with Lentibacillus daqui ZS110521 (97.5% similarity) and L. garicola SL-MJ1 (95.9% similarity). The major cellular fatty acids (≥ 5%) were anteiso-C, ananteiso-C and iso-C. The respiratory quinone was MK-7 and peptidoglycan contained meso-DAP. The polar lipid profile consisted of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and an unidentified phospholipid. The genome size of strain N15 was 4.5 Mb, and the DNA G + C content was 40.1%. The nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain N15 and L. daqui ZS110521 were 77.8% and 22.6%, respectively, which were significantly below the recommended thresholds (ANI < 95-96% and dDDH < 70%) for species delineation. Based on the phenotypic, phylogenetic, chemotaxonomic, and genomic results from this study, strain N15 represents a novel species in genus Lentibacillus, for which the name Lentibacillus songyuanensis sp. nov. is proposed, the type strain is N15 (= MCCC 1K09143 = KCTC 43718).