Comparative genomic analysis of the genus Weissella and taxonomic study of Weissella fangxianensis sp. nov., isolated from Chinese rice wine starter

In this study, three lactic acid bacteria, namely, HBUAS51963T, HBUAS51964 and HBUAS51965, were isolated from Chinese rice wine starter sampled in Fangxian County, PR China. All were non-motile, non-spore-forming and Gram-positive spherical cells. Their taxonomic status was characterized using a polyphasic approach. Genome-based analysis revealed that all three strains were phylogenomically related to Weissella thailandensis KCTC 3751T and Weissella paramesenteroides ATCC 33313T. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between the three strains and the phylogenetically related type strains were less than 54.8 and 93.8 %, respectively, and thus, they were below the thresholds of dDDH and ANI for species definition. The genomic DNA G+C content was 38.6 mol %. The predominant fatty acid methyl esters (>10 %) were C16 : 0, C19 : 0 cyc11 and summed feature 10 (C18 : 1 cyc11 and/or ECL 17.834). The polar lipids in the cells of strain HBUAS51963T were mainly phosphatidylglycerol, diphosphatidylglycerol, unidentified glycolipids, phospholipids and lipids. Finally, the three strains were capable of producing d-lactic acid (4.29 g l-1) and various organic acids such as tartaric, acetic, lactic and succinic acids. Overall, the results of genotypic, phenotypic and genomic analyses suggest that the three strains represent a new species of the genus Weissella, for which the name Weissella fangxianis sp. nov. is proposed. The type strain is HBUAS51963T (=GDMCC 1.3506T= JCM 35803T).