Bacillus paralicheniformis sp. nov., isolated from fermented soybean paste

Abstract

An isolate of a Gram-stain-positive, facultatively anaerobic, motile, rod-shaped, endospore-forming bacterium was recovered from soybean-based fermented paste. Phylogenetic analysis of the 16S rRNA gene indicated that the strain was most closely related to Bacillus sonorensis KCTC-13918T (99.5 % similarity) and Bacillus licheniformis DSM 13T (99.4 %). In phenotypic characterization, the novel strain was found to grow at 15–60 °C and to tolerate up to 10 % (w/v) NaCl. Furthermore, the strain grew in media with pH 6–11 (optimal growth at pH 7.0–8.0). The predominant cellular fatty acids were anteiso-C15 : 0 (37.7 %) and iso-C15 : 0 (31.5 %). The predominant isoprenoid quinone was menaquinone 7 (MK-7). The cell-wall peptidoglycan contained meso-diaminopimelic acid. A draft genome sequence of the strain was completed and used for phylogenetic analysis. Phylogenomic analysis of all published genomes of species in the B. licheniformis group revealed that strains belonging to B. licheniformis clustered into two distinct groups, with group 1 consisting of B. licheniformis DSM 13T and 11 other strains and group 2 consisting of KJ-16T and four other strains. The DNA G+C content of strain KJ-16T was 45.9 % (determined from the genome sequence). Strain KJ-16T and another strain from group 2 were subsequently characterized using a polyphasic taxonomic approach and compared with strains from group 1 and another closely related species of the genus Bacillus. Based upon the consensus of phylogenetic and phenotypic analyses, we conclude that this strain represents a novel species within the genus Bacillus, for which the name Bacillus paralicheniformis sp. nov. is proposed, with type strain KJ-16T ( = KACC 18426T = NRRL B-65293T).