Lactococcus fujiensis sp. nov., a lactic acid bacterium isolated from vegetable matter

Abstract

Three strains of lactic acid bacteria, designated NJ 317T, NJ 414 and NJ 415, were isolated from the outer leaves of Chinese cabbages (Brassica rapa L. var. glabra Regel) and characterized taxonomically. The strains were Gram-reaction-positive, catalase-negative, facultatively anaerobic cocci that did not produce gas from glucose and formed l-lactic acid. The major fatty acids were C18 : 1ω9c, C16 : 0, C14 : 0 and summed feature 10. Morphological, physiological and phylogenetic data indicated that the strains belonged to the genus Lactococcus. These strains shared similar phenotypic characteristics and exhibited DNA relatedness values >96.6 % to each other, indicating that they represent a single species. The DNA G+C contents of the three strains were 42.1–42.5 mol%. 16S rRNA gene sequences of the novel strains were determined and aligned with those of other species of the genus Lactococcus. On the basis of phylogenetic analysis the three strains grouped with other members of the genus Lactococcus. Lactococcus lactis and Lactococcus garvieae were the most closely related species, sharing a sequence similarity value of 94.4 % with the three strains. Ribotyping patterns, however, revealed that these strains were well-separated from reference strains of species of the genus Lactococcus and DNA–DNA hybridization studies indicated that the novel strains had low levels (<20.2 %) of DNA relatedness with reference strains of L. lactis, L. garvieae and other type strains of previously described species, showing that they represent a different species. Based on this evidence, strains NJ 317T, NJ 414 and NJ 415 represent a novel species of the genus Lactococcus, for which the name Lactococcus fujiensis sp. nov. is proposed. The type strain is NJ 317T ( = JCM16395T  = CGMCC 1.10453T).