Purification and characterization of low molecular weight alkaline xylanase from Neosartorya tatenoi KKU-CLB-3-2-4-1

抄録

A low molecular weight alkaline xylanase from Neosartorya tatenoi KKU-CLB-3-2-4-1 was purified to homogeneity by ammonium sulfate precipitation, Sephadex G-100 and DEAE-cellulose column chromatography. The xylanase was purified 32.09 fold, with the specific activity of 16.07 U mg⁻¹ protein and a recovery yield of 2.67%. The purified xylanase was estimated by SDS-PAGE with a molecular weight of 20 kDa. The purified xylanase was active at pH 10.0 and retained over 75% of the original activity in pH range 7.0–11.0 after incubation at 4 °C for 24 h. The optimum temperature of the purified xylanase was 45 °C. As for thermo-stability, more than 80% of original xylanase activity was retained after heating at 45 °C for 120 min. Xylanase activity was stimulated by Ag⁺ and inhibited by Hg²⁺. The purified xylanase was specific to beechwood xylan, birchwood xylan and oat spelt xylan. The K_m and V_max values for beechwood xylan were 10.34 mg/mL and 45.66 μmol/min/mg, respectively. In addition, the xylanase hydrolyzed beechwood xylan yielded mainly xylotriose and xylotetraose as end products, suggesting it was an endo-xylanase. Thus, its properties may make it attractive for application in the pulp and paper industry.