Abstract

Fungal xylanase was produced from lignocellulosic palm wastes through combined solid-state fermentation (SSF) and submerged fermentation (SmF) by Aspergillus tubingensis TSIP9 in a helical-impeller equipped bioreactor. The combined SSF–SmF promoted the xylanase production by 15 and 70% higher than SSF and SmF, respectively. Sequential purification yielded 7.4-fold purified xylanase with 9.07% recovery. The maximum activities of crude and purified xylanase were observed at the same pH of 5.0 and the same temperature of 50 °C while purified xylanase is more active and highly stable at a wider pH range of 3–8 and temperature of 30−60 °C. The half-life of purified xylanase at various temperatures was also much improved by 2−8 folds compared to crude xylanase. Michaelis–Menten constants, V_max and K_m, for purified xylanase are 2,602.8 U/mg and 32.4 mg/mL, respectively. Purified xylanase activity was most enhanced with Ca²⁺ followed by Zn²⁺ and Fe²⁺ at 10 mM while significantly inhibited by Co²⁺, Cu²⁺, Pb²⁺, and Ag⁺. This study has shown the effectiveness of combined SSF–SmF for xylanase production and superior properties of purified xylanase for industrial processes.

摘要

在配备螺旋叶轮的生物反应器中，通过组合固态发酵 (SSF) 和管状曲霉 TSIP9 的深层发酵 (SmF) 从木质纤维素棕榈废料中生产真菌木聚糖酶。SSF-SmF 的组合使木聚糖酶的产量分别比 SSF 和 SmF 高 15% 和 70%。连续纯化产生 7.4 倍纯化的木聚糖酶，回收率为 9.07%。在相同的 pH 值 5.0 和相同的温度 50 °C 下观察到粗制和纯化木聚糖酶的最大活性，而纯化的木聚糖酶在 3-8 的更宽 pH 范围和 30-60 °C 的温度下更具活性和高度稳定性. 与粗制木聚糖酶相比，纯化的木聚糖酶在不同温度下的半衰期也大大提高了 2-8 倍。米氏常数，V_{对于纯化的木聚糖酶， max}和K _m分别为 2,602.8 U/mg 和 32.4 mg/mL。^{纯化的木聚糖酶活性在10 mM Ca 2+}中增强最大，其次是Zn ²⁺和Fe ^{2+ ，而Co 2+}、Cu ²⁺、Pb ²⁺和Ag ⁺显着抑制。该研究显示了组合 SSF-SmF 对木聚糖酶生产的有效性以及纯化木聚糖酶在工业过程中的优越性能。