Leuconostoc koreense sp. nov., isolated from kimchi, a fermented vegetable.

Abstract

The novel strain CBA3628^T was isolated from kimchi, a Korean fermented vegetable. CBA3628^T is a cocci-shaped, Gram-stain-positive, catalase- and oxidase-negative and facultatively anaerobic bacterium. The results of phylogenetic analysis based on 16S rRNA gene sequencing indicated that CBA3628^T represented a member of the genus Leuconostoc of the family Leuconostocaceae. CBA3628^T has a circular chromosomal genome and three plasmids of 1 864 558 bp (37% DNA G+C content), containing 1,887 genes, 1,762 predicted protein-coding genes, 4 complete rRNA loci and 70 tRNA genes. The cells were non-haemolytic, non-motile and non-spore forming. The optimal growth of CBA3628^T occurred at 30 °C, pH 6.0 and with 0-2% (w/v) NaCl. The major polar lipids of CBA3628^T were diphosphatidylglycerol and phosphatidylglycerol. The major fatty acids (>10%) of CBA3628^T were C_{16  :  0}, C_{20  :  0} and C_19 : 0 cyclo ω8c. CBA3628^T contained A3α-type peptidoglycans. CBA3628^T was most closely related to Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293^T, L. mesenteroides subsp. dextranicum DSM 20484^T and L. suionicum DSM 20241^T with 99.52% 16S rRNA gene sequence similarity. However, the average nucleotide identities of 91.9%, 91.7% and 91.1% and the digital DNA-DNA hybridisation values of 45.6%, 45.4% and 45.4% indicated that the novel isolate represented a distinct species. Phylogenetic analyses of both the 16S rRNA gene and genome sequences revealed that CBA3628^T formed a distinct phylogenetic lineage within the genus Leuconostoc and was most closely related to Leuconostoc litchii MB7^T. The ANI and dDDH values between CBA3628^T and L. litchii MB7^T were 84.9 and 22.8%, respectively. Functional genes belonging to COG categories E, J and K were enriched in the genome of CBA3628^T (>7.9%). On the basis of its physiological, chemotaxonomic, phylogenetic and genomic properties, strain CBA3628^T represents a novel species from the genus Leuconostoc, for which we propose the name Leuconostoc koreense sp. nov., with the type strain CBA3628^T (= KACC 23049^T = DSM 116836^T).