Graduate School, Khon Kaen University, Khon Kaen, 40002, Thailand.
Biology Program, Faculty of Science, Buriram Rajabhat University, Buriram, 31000, Thailand.
Sci Rep. 2020 Dec 10;10(1):21663. doi: 10.1038/s41598-020-78670-y.
We investigated the properties of the low molecular weight thermo-alkali-stable and mercury ion-tolerant xylanase production from Thermomyces dupontii KKU-CLD-E2-3. The xylanase was purified to homogeneity by ammonium sulfate, Sephadex G-100 and DEAE-cellulose column chromatography which resulted 27.92-fold purification specific activity of 56.19 U/mg protein and a recovery yield of 2.01%. The purified xylanase showed a molecular weight of 25 kDa by SDS-PAGE and the partial peptide sequence showed maximum sequence homology to the endo-1,4-β-xylanase. The optimum temperature and pH for its activity were 80 °C and pH 9.0, respectively. Furthermore, the purified xylanase can maintain more than 75% of the original activity in pH range of 7.0-10.0 after incubation at 4 °C for 24 h, and can still maintain more than 70% of original activity after incubating at 70 °C for 90 min. Our purified xylanase was activated by Cu and Hg up to 277% and 235% of initial activity, respectively but inhibited by Co, Ag and SDS at a concentration of 5 mM. The K and V values of beechwood xylan were 3.38 mg/mL and 625 µmol/min/mg, respectively. Furthermore, our xylanase had activity specifically to xylan-containing substrates and hydrolyzed beechwood xylan, and the end products mainly were xylotetraose and xylobiose. The results suggested that our purified xylanase has potential to use for pulp bleaching in the pulp and paper industry.
我们研究了 Thermomyces dupontii KKU-CLD-E2-3 产生的低分子量耐热碱和汞离子的木聚糖酶的性质。木聚糖酶通过硫酸铵、Sephadex G-100 和 DEAE-纤维素柱层析纯化至均一性，比活力特异性提高了 27.92 倍，达到 56.19 U/mg 蛋白，回收率为 2.01%。纯化的木聚糖酶通过 SDS-PAGE 显示分子量为 25 kDa，部分肽序列与内切-1,4-β-木聚糖酶显示最大序列同源性。其活性的最适温度和 pH 分别为 80°C 和 pH 9.0。此外，在 4°C 孵育 24 小时后，在 pH 7.0-10.0 范围内，纯化的木聚糖酶可保持超过 75%的原始活性，在 70°C 孵育 90 分钟后仍可保持超过 70%的原始活性。我们纯化的木聚糖酶被 Cu 和 Hg 分别激活至初始活性的 277%和 235%，但在 5 mM 浓度下被 Co、Ag 和 SDS 抑制。桦木木聚糖的 K 和 V 值分别为 3.38 mg/mL 和 625 µmol/min/mg。此外，我们的木聚糖酶对含木聚糖的底物具有活性，可水解桦木木聚糖，其末端产物主要为木四糖和木二糖。结果表明，我们纯化的木聚糖酶在制浆造纸工业中具有用于纸浆漂白的潜力。
