Purification and characterization of a novel detergent- and organic solvent-resistant endo-beta-1,4-glucanase from a newly isolated basidiomycete Peniophora sp. NDVN01

A novel extracellular endoglucanase from a basidiomycete strain Peniophora sp. NDVN01 was purified 2.8-fold to homogeneity through ammonium sulfate precipitation and gel filtration with Bio-Gel P-100 and Sephadex G-75. The endoglucanase had a specific activity of 163.8 U/mg protein and a molecular mass of 32 kDa. Optimum temperature and pH were at 60 °C and 4.5, respectively. The enzyme was stable at up to 42 °C and in the pH range of 3.5–5.5 with a residual activity of over 80% for 24 h of treatment. Ni^2+ activated but other metal ions showed no or slight inhibitory effect on the enzyme activity. The endoglucanase showed a high resistance to most tested detergents and organic solvents. The endoglucanase catalyzed the hydrolysis of barley β-glucan and carboxymethyl cellulose (CMC), but not toward xylan, locust bean gum, and Avicel, typical substrates for xylanase, mannanase and exoglucanase, respectively. The kinetic parameters Km, Vmax, Kcat, and Kcat/Km for barley β-glucan and carboxymethyl cellulose were 5.9 mg/mL, 9804 U/mg, 6.14 × 10^5 min^–1, and 1.04 × 105 and 34.8 mg/mL, 1825 U/mg, 1.14 × 10^5 min^–1, and 0.33 × 10^4, respectively. Hydrolysis of CMC liberated cellobiose, cellotriose, cellotetraose, and a detectable amount of glucose. These results suggest that the endoglucanase might potentially be used in enzymatic reactions and to investigate the efficacy of feed enzymes.