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

Abstract

Two novel Gram-positive bacteria, designated strains REN8T and REN14T, were isolated from baijiu pit mud in Sichuan Province, China. REN8T achieved the best growth at 37°C, a pH of 8.0, and a NaCl concentration of 2%, while REN14T 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 REN8T and REN14T were clustered with the genus Planococcus. The genomic DNA G + C contents of REN8T and REN14T were 46.7 and 45.1 mol%, respectively. The dDDH and ANI values were 24.5 and 80.43% between REN8T and P. salinarum (the most closely related type strain) and 25.1 and 82.42% between REN14T and P. soli (the most closely related type strain). Genomic analysis showed that several carbohydrate-active enzymes and secondary metabolite gene clusters existed in REN8T and REN14T. Chemotaxonomic characteristics of REN8T and REN14T 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 REN8T (=JCM 33964T = GDMCC 1.2213T), and the name Planococcus beijingensis sp. nov. is proposed for the type strain REN14T (=JCM 34410T = GDMCC 1.2209T). The addition of REN8T and REN14T 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.