Homology analysis of 35 β-glucosidases in Oenococcus oeni and biochemical characterization of a novel β-glucosidase BGL0224.

β-Glucosidases play an important role in food industry. Oenococcus oeni are typical lactic acid bacteria that initiate malolactic fermentation of wines. 35 β-glucosidases from O. oeni were selected and their conserved domains and evolutionary relationships were further explored in this study. The homology analysis results indicated that 35 β-glucosidases were basically derived from GH1 and GH3 family. A novel β-glucosidase was successfully expressed and characterized. The recombinant protein, referred to as BGL0224, consisted of a total 480 amino acids with an apparent molecular weight of 55.15 kDa and was classified as GH1 family. It achieved the highest activity at pH 5.0 and 50 °C. The activity and stability were significantly increased when 12% ethanol was supplemented to the enzyme. Using p-NPG as substrate, the Km, Vmax and Kcat of BGL0224 were 0.34 mM, 382.81 U/mg and 351.88 s-1, respectively. In all, BGL0224 has good application prospects in food industry.