乙酰木聚糖酯酶协同木聚糖酶降解木聚糖的研究

Combinative Degradation of Xylan with Acetyl Xylan Esterase and Xylanase

摘要:

探讨了宇佐美曲霉（Aspergillus usamii） 乙酰木聚糖酯酶和第10、11家族木聚糖酶之间的协同作用。利用作者所在实验室构建保藏的3株工程酵母Pichia pastoris GS115/Auaxe、GS115/Auxyn11A和GS115/Auxyn10A进行甲醇诱导发酵，分别获得重组乙酰木聚糖酯酶和木聚糖酶。在木聚糖酶最适pH、40 ℃、料液质量体积比1 g∶60 mL、水解2 h的条件下分别研究了不同加酶量作用于小麦麸皮时生成的还原糖量。结果表明，乙酰木聚糖酯酶与第11家族木聚糖酶有更好的协同作用，并在添加量比（酶活力比）为5∶1时所测协同效果最好，还原糖生成量较木聚糖酶单独作用增加了46%。因此，在乙酰木聚糖酯酶的作用下，木聚糖上乙酰基的去除，对提高木聚糖酶对木聚糖的水解效率具有重要作用。

Abstract:

The synergetic effect of the recombinant acetylxylan esterase and xylanase from Aspergillus usamii(abbreviated as reAuAxe, reAuXyn11A, reAuXyn10A, respectively) was investigated. The fermentation of Pichia pastoris GS115/Auaxe, GS115/Auxyn11A and GS115/Auxyn10A was carried out using methanol as inducer and reAuAxe, reAuXyn11A and reAuXyn10A were successfully expressed. The amounts on the release of reducing sugar were optimized with enzyme concentration when incubated for 2 h at the optimal pH under 40 ℃ with the solid-liquid ratio of 1 g∶60 mL. A better synergistic effect was found when acetylxylan esterase and reAuXyn11A were combined. Comparing to use xylanase alone, the released reduce sugar could increase by 46% when reAuAxe and reAuXyn11A were added with a ratio of 5∶1. The removal of the O-acetyl groups from the xylose residues by acetylxylan esterase was necessary and important for the efficiency improvement of xylan hydrolysis.