Characterization of glycosidases produced by Pseudomonas fluorescens 26 ¹

Six synthetic glycosides were used to characterize glycosidic activities of a cell-free filtrate of Pseudomonas fluorescens 26. The filtrate was prepared after growing the bacterium in glucose-enriched minimal growth broth. Temperature and pH optima for glycosidic activity were as follows, respectively, β-D-fucosidase: 15°C and 6.0, β-D-mannosidase: 25°C and 6.0, β-D-glucosidase: 25°C and 5.5, β-D-galactosidase: 30°C and 6.5, N-acetyl-β-D-glucosaminidase: 45°C and 7.0, and N-acetyl-β-D-galactosaminidase: 45°C and 6.0. Activation energies of B-D-galactosidase, β-D-mannosidase, β-D-glucosidase and N-acetyl-β-D-glucosaminidase were 25.4, 12.3, 9.8 and 6.0 Kcal/mol, respectively. β-D-fucosidase and N-acetyl-β-D-galactosaminidase appeared to have non-Arrhenius behavior, so activation energies were not calculated for them. All six glycosidases were heat-sensitive to conditions of pasteurization of milk.