Paracoccus yibinensis sp. nov., a novel bacterium with astaxanthin producing isolated from the environment of Chinese distilled Baijiu.

An aerobic, Gram-stain-negative bacterium, designated as strain WLY502, was isolated from the environment of Baobaoqu starter production. The strain was with a short rod shape cells 0.5-0.7 μm wide and 1.1-2.0 μm long, arranged singly or in pairs. The isolate was able to grow at temperatures of 20-37 °C (optimum growth at 25 °C), at pH 5.0-10.0 (optimum growth at pH 7.0) and in the presence of 0-5% (w/v) NaCl (optimum growth with 0% NaCl). Ribose, xylose, arabinose, mannose, glucose and galactose were the major cell-wall sugar. The meso-diaminopimelic acid (meso-DAP) was the diagnostic amino acid. The main polar lipids of strain WLY502 included diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), unidentified aminolipids (UAL 1-2), unidentified aminophospholipid (UAPL), unidentified aminophospholipid (UAPL), unidentified phospholipid (UPL), unidentified lipids (UL 1-5), glycolipid (GL). Ubiquinone Q-10 was predominant menaquinone and C ω7c (80.5%) was the major fatty acid. Comparisons of 16S rRNA gene sequence indicated that strain WLY502 was most closely related to Paracoccus acridae SCU-M53 (98.48%), Paracoccus haematequi M1-83 (98.40%). The average nucleotide identity (ANI) values strain WLY502 and the two type strains mentioned above were 91.19% and 70.96%. The average amino identity (AAI) value between them were 93.42% and 87.19%. Additionally, the digital DNA-DNA hybridization (dDDH) value between them is 42.9% and 30.1%. The genomic DNA G + C content was 64.99%. Strain WLY502 could produce astaxanthin and contains several genes (such as MalK, UgpE, UgpA, PRK07067, PBP2 TMBP ike, YcjU, YjiC, crtI-fam, crtY, ERG9, and IspA) involved in astaxanthin. Therefore, strain WLY502 may have development and utilisation value in flavouring agents. Based on the evidence presented, strain WLY502 (CICC 25237 = JCM 36429) is proposed as the type strain of a novel species, designated as Paracoccus yibinensis sp. nov.