Abstract

A Gram-reaction-positive, strictly aerobic, motile, endospore- forming, and rod-shaped bacterial strain designated 135PIL107-10T was isolated from a sponge on Jeju Island, and its taxonomic position was investigated using a polyphasic approach. Strain 135PIL107-10T grew at 20–37°C (optimum temperature, 25°C) and pH 6.0–10.0 (optimum pH, 6.0) on marine and R2A agars. Based on 16S rRNA gene phylogeny analysis, the novel strain formed a new branch within the genus Bacillus of the family Bacillaceae, and formed clusters with Bacillus thaohiensis NHI-38T (96.8%), Bacillus fengqiuensis NPK15T (96.7%), and Bacillus songklensis CAU 1033T (96.7%). Lower sequence similarities (97.0%) were found with the type strains of all other recognized members of the genus Bacillus (95.6–96.8% similarity). The G + C content of the genomic DNA was 43.6 mol%. The predominant respiratory quinone was menaquinone-7 and the major fatty acids were iso-C15:0 and iso-C17:1ω10c. The overall polar lipid patterns were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. The diagnostic diamino acid in the cell-wall peptidoglycan was meso-diaminopimelic acid. The isolate therefore represents a novel species, for which the name Bacillus spongiae sp. nov. is proposed, with the type strain 135PIL107-10T (= KACC 19275T = LMG 30080T).

• Keywords: Bacillus spongiae; 16S rRNA gene; polyphasic taxonomy; sponge