Two novel Planococcus species isolated from baijiu pit mud with potential application in brewing

Two novel Gram-positive bacteria, designated strains REN8^T and REN14^T, were isolated from baijiu pit mud in Sichuan Province, China. REN8^T achieved the best growth at 37°C, a pH of 8.0, and a NaCl concentration of 2%, while REN14^T displayed optimal growth at 37°C, a pH of 6.0, and a NaCl concentration of 1%. 16S rRNA and genomic phylogenetic analysis showed that REN8^T and REN14^T were clustered with the genus Planococcus. The genomic DNA G + C contents of REN8^T and REN14^T were 46.7 and 45.1 mol%, respectively. The dDDH and ANI values were 24.5 and 80.43% between REN8^T and P. salinarum (the most closely related type strain) and 25.1 and 82.42% between REN14^T and P. soli (the most closely related type strain). Genomic analysis showed that several carbohydrate-active enzymes and secondary metabolite gene clusters existed in REN8^T and REN14^T. Chemotaxonomic characteristics of REN8^T and REN14^T included major fatty acids, predominant menaquinones, and polar lipids, all of which were consistent with the genus Planococcus. Based on the polyphasic taxonomic method, these two strains represent two novel species of the genus Planococcus; the name Planococcus beigongshangi sp. nov. is proposed for the type strain REN8^T (=JCM 33964^T = GDMCC 1.2213^T), and the name Planococcus beijingensis sp. nov. is proposed for the type strain REN14^T (=JCM 34410^T = GDMCC 1.2209^T). The addition of REN8^T and REN14^T might improve the quality of huangjiu by considerably increasing the amino acid nitrogen content and acidity and decreasing the bioamine content, with no significant change in alcohol content.