Lysinibacillus alkaliphilus sp. nov., an extremely alkaliphilic bacterium, and emended description of genus Lysinibacillus.

Abstract

A novel aerobic, alkaliphilic, Gram-staining-positive, endospore-forming bacterium, strain OMN17T, was isolated from a typical sandy loam soil under long-term OMN fertilization (half organic manure N plus half mineral N fertilizer) in northern China and was subjected to a polyphasic taxonomic study. The best growth was achieved at 30 °C and pH 8-10 in medium containing 0.5% (w/v) NaCl. The cell-wall peptidoglycan of strain OMN17T was type A4α; (l-Lys-Gly-d-Asp) and the cell-wall sugars were ribose, traces of galactose and arabinose. The only respiratory quinone found in strain OMN17T was menaquinone 7 (MK-7). The major cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0. The major polar lipids were found to be phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Phylogenetic analysis of strain OMN17T based on the 16S rRNA gene sequence showed that the strain was most closely related to Lysinibacillus halotolerans (97.8%), Lysinibacillus sinduriensis (97.5%), Lysinibacillus chungkukjangi (97.4%) and Lysinibacillus xylanilyticus (97.0%). The DNA-DNA hybridization results indicated that this strain was distinct from other species of the genus Lysinibacillus, the degree of relatedness being 21.8 ± 0.2% with L. halotolerans, 45.6 ± 1.8% with L. sinduriensis, 33.7 ± 1.2% with L. chungkukjangi and 23.7 ± 0.7% with L. xylanilyticus. The DNA G+C content of strain OMN17T was 38.1 mol%. The phenotypic, chemotaxonomic and genetic analyses identified strain OMN17T as a novel species of the genus Lysinibacillus, for which the name Lysinibacillus alkaliphilus sp. nov. is proposed. The type strain is OMN17T ( = DSM 28019T = CCTCC AB 2014073T). An emended description of the genus Lysinibacillus is also provided.