Lactococcus kimchii sp. nov., a new lactic acid bacterium isolated from kimchi

Abstract

A coccus strain designated S-13^T was isolated from commercial baechu-kimchi in Korea. Comparison of the 16S rRNA gene sequence indicated that strain S-13^T had the highest similarity to <i>Lactococcus taiwanensis</i> 0905C15^T (97.9 %), <i>Lactococcus lactis</i> subsp. <i>tructae</i> L105^T (97.6 %), <i>Lactococcus lactis</i> subsp. <i>cremoris</i> NCDO 607^T (97.5 %), <i>Lactococcus lactis</i> subsp. <i>hordniae</i> NBRC 100931^T (97.2 %), and <i>Lactococcus lactis</i> subsp. <i>lactis</i> JCM 5805^T (97.2 %). The detailed phylogenetic analyses based on the 16S rRNA, <i>rpoB</i> and <i>recA</i> genes indicated that S-13^T was separated from the other species and subspecies in the genus <i>Lactococcus</i>. The DNA-DNA relatedness between S-13^T and closely related type strains, such as <i>L. taiwanensis</i> 0905C15^T, <i>L. lactis</i> subsp. <i>tructae</i> L105^T, <i>L. lactis</i> subsp. <i>cremoris</i> NCDO 607^T, <i>L. lactis</i> subsp. <i>hordniae</i> NBRC 100931^T, and <i>L. lactis</i> subsp. <i>lactis</i> JCM 5805^T was 25.6, 20.4, 25.1, 20.2 and 21.7 %, respectively. The major fatty acids were C_{16 : 0}, cyclo-C_{19 : 0}ω8<i>c</i> and C _{14 : 0}. The DNA G+C content of S-13^T was 39.4 mol%. From the results of the phenotypic characteristics and chemotaxonomic analysis, it was concluded that strain S-13^T represents a novel species in the genus <i>Lactococcus</i> for which the name <i>Lactococcus kimchii</i> sp. nov. (=KCTC 21096^T=NBRC 113348^T) is proposed.