低聚木糖生产用木聚糖酶的选择性合成

Selective biosynthesis of xylanases for xylo-oligosaccharides production by Trichoderma reesei Rut C-30

以里氏木霉(Trichoderma reesei)Rut C-30为产酶菌,研究了碳源、碳氮比对木聚糖酶酶系组成的影响。低分子量组分较多的木聚糖有利于促进内切-β-木聚糖酶的合成,酶解产物中低聚木糖的含量较高(80.70%)。低碳氮比有利于促进内切-β-木聚糖酶的合成,抑制外切-β-木糖苷酶的合成。以低分子量较多的木聚糖(7g??L)为碳源,降低培养基的碳氮比为4.0,调控培养60 h,用该木聚糖酶酶解粗木聚糖,产物中低聚木糖占总糖的B6.32％。

The effects of carbon source and C/N ratio on xylanase synthesis by Trichoderma reesei Rut C-30 have been studied.Low molecular weight components of xylan are favorable in inducing endo-1,4-β-D-xylanase,xylan A,which was the solid residue after the enzymatic hydrolysis of corncob xylan and was determined to contain much low molecular weight compo- nents,was used as the carbon source for xylanase synthesis,xylo-oligosacchrides were 80.70% of the total sugar in hydrolysate; low ratio of carbon to nitrogen could stimulate the synthesis of endo-1,4-β-D-xylanase and depress the synthesis of exo-β-xy- losidase,which enchanced the synthesis of xylosidase-poor xylanase.Purer endo-1,4-β-D-xylanase could be prepared through controlled cultivation of Trichoderma reesei Rut C-30 with xylan A as the carbon source.Xylanase could be obtained after 60 h of cultivation with 7.0 g/L of carbon with C/N ratio of 4.0.When thus prepared xylanase was used in enzymatic hydrolysis,the ratio of xylo-ohgosacchrides to total sugar could reach 86.32%.