Leuconostoc aquikimchii sp. nov., a lactic acid bacterium isolated from cabbage watery Kimchi

Abstract

Two Gram-stain-positive, facultatively anaerobic, non-hemolytic, coccoid-shaped bacterial strains, designated MS01T and MS02, were isolated from cabbage watery kimchi in the Republic of Korea. Cellular growth occurred at 5-25 ℃ (optimum, 20 ℃), pH 5-8 (optimum, pH 7) and in the presence of 0-5% (w/v) NaCl (optimum, 1%). Results of 16S rRNA gene-based phylogenetic analyses showed that strains MS01T and MS02 shared identical sequences, clustered within the Leuconostoc clade in phylogenetic trees, and were most closely related to Leuconostoc inhae IH003T and Leuconostoc gasicomitatum LMG 18811T with sequence similarities of 98.74%. The complete whole-genome sequences of strains MS01T and MS02 measured 2.04-2.06 Mbp and harbored a 50.6 kb plasmid, with DNA G + C contents of 37.7% for both. Based on average nucleotide identities (ANI) and digital DNA-DNA hybridization (dDDH) values, both strains were confirmed to belong to the same species but showed ≤ 85.9% ANI and ≤ 29.9% dDDH values to other Leuconostoc species, indicating that they represent a novel species. Metabolic pathway reconstruction revealed that both strains perform heterolactic acid fermentation, producing lactate, acetate, and ethanol. Chemotaxonomic analyses, including cellular fatty acids, polar lipids, and peptidoglycan amino acid, confirmed the inclusion of both strains within the genus Leuconostoc. Based on the phylogenetic, genomic, and phenotypic characterization, strains MS01T and MS02 were considered to represent a novel species within the genus Leuconostoc, for which the name Leuconostoc aquikimchii sp. nov. is proposed with MS01T (= KACC 23748T = JCM 37028T) as the type strain.