β-Glucosidase Activity in a Lactobacillus Plantarum Wine Strain

A collection of malolactic bacteria isolated from musts and wines of northwestern Spain (Rias Baixas) was used to determine their ability to produce aryl β-D-glucosidases. A β-glucosidase (EC 3.2.1.21) was purified to homogeneity from cell-free extracts of a strain of Lactobacillus plantarum. The enzyme had a molecular mass of about 40 kDa, as determined by molecular-exclusion chromatography. The enzyme was most active at pH 5.0, and was stable between pH 4.5 and 7.5. The optimum temperature was 45 °C and the enzyme was active against a wide range of aryl β-glucosides and β-linked disaccharides. The Km and Vmax values for 4-nitrophenyl-β-D-glucopyranoside were 1.82 mM and 4.89 nmol/ml/min, respectively.