Lactobacillus suantsaicola sp. nov. and Lactobacillus suantsaiihabitans sp. nov., isolated from suan-tsai, a traditional fermented mustard green product of Taiwan

Abstract

Four Gram-stain-positive strains, R7^T, R11, R19^T and R27, were isolated from suan-tsai, a traditional fermented mustard green product of Taiwan. Cells were rod-shaped, non-motile, non-haemolytic, asporogenous, facultatively anaerobic, heterofermentative, and did not exhibit catalase and oxidase activities. Comparative analyses of 16S rRNA, <i>pheS</i> and <i>rpoA</i> gene sequences demonstrated that these novel strains were members of the genus <i>Lactobacillus</i>. 16S rRNA and the concatenated <i>pheS</i> and <i>rpoA</i> gene sequence similarities between strains R7^T and R11, and strains R19^T and R27 were very high (>99.8 % similarity), respectively. On the basis of 16S rRNA gene sequence similarities, the type strains of <i>Lactobacillus paralimentarius</i> (98.5 %), <i>Lactobacillus kimchii</i> (98.5 %), <i>Lactobacillus alimentarius</i> (98.1 %) and <i>Lactobacillus bobalius</i> (98.1 %) were the closest neighbours to strains R7^T and R11, and the type strains of <i>Lactobacillus brevis</i> (98.9 %), <i>Lactobacillus cerevisiae</i> (98.4 %), <i>Lactobacillus hammesii</i> (98.4 %), <i>Lactobacillus koreensis</i> (98.4 %) and <i>Lactobacillus yonginensis</i> (98.0 %) were the closest neighbours to strains R19^T and R27, respectively. The average nucleotide identity values of R7^T and R19^T with the closely related type strains were 78.9-80.1% and 75.7-80.5 %, respectively. The digital DNA-DNA hybridization values were 22.8-23.6% and 21.0-23.1 %, respectively. Phenotypic and genotypic test results demonstrated that these strains represent two novel species of the genus <i>Lactobacillus</i>, for which the name <i>Lactobacillus suantsaicola</i> sp. nov. (R7^T=BCRC 81127^T=NBRC 113530^T) and <i>Lactobacillus suantsaiihabitans</i> sp. nov. (R19^T=BCRC 81129^T=NBRC 113532^T) are proposed.