Streptomyces beigongshangae sp. nov., isolated from baijiu fermented grains, could transform ginsenosides of Panax notoginseng .

A Gram-stain-positive actinomycete, designated REN17 ^T , was isolated from fermented grains of Baijiu collected from Sichuan, PR China. It exhibited branched substrate mycelia and a sparse aerial mycelium. The optimal growth conditions for REN17 ^T were determined to be 28 °C and pH 7, with a NaCl concentration of 0 % (w/v). ll-Diaminopimelic acid was the diagnostic amino acid of the cell-wall peptidoglycan and the polar lipids were composed of phosphatidylethanolamine, phosphatidylinositol, an unidentified phospholipid, two unidentified lipids and four unidentified glycolipids. The predominant menaquinone was MK-9 (H ₂ ), MK-9 (H ₄ ), MK-9 (H ₆ ) and MK-9 (H ₈ ). The major fatty acids were iso-C _{16 : 0} . The 16S rRNA sequence of REN17 ^T was most closely related to those of Streptomyces apricus SUN 51 ^T (99.8 %), Streptomyces liliiviolaceus BH-SS-21 ^T (99.6 %) and Streptomyces umbirnus JCM 4521 ^T (98.9 %). The digital DNA-DNA hybridization, average nucleotide identity and average amino acid identify values between REN17 ^T and its closest replated strain, of S. apricus SUN 51 ^T , were 35.9, 88.9 and 87.3 %, respectively. Therefore, REN17 ^T represents a novel species within the genus Streptomyces , for which the name Streptomyces beigongshangae sp. nov. is proposed. The type strain is REN17 ^T (=GDMCC 4.193 ^T =JCM 34712 ^T ). While exploring the function of the strain, REN17 ^T was found to possess the ability to transform major ginsenosides of Panax notoginseng (Burk.) F.H. Chen (Araliaceae) into minor ginsenoside through HPLC separation, which was due to the presence of β-glucosidase. The recombinant β-glucosidase was constructed and purified, which could produce minor ginsenosides of Rg3 and C-K. Finally, the enzymatic properties were characterized.