采用冻干浓缩,硫酸铵盐析,Sephacryl S-200 High Resolution凝胶柱层析,HiTrap Desalting凝胶柱脱盐,HiTrapTMSP(HP)离子柱层析对里氏木霉EIM-30的发酵液进行分离纯化,获得两个纯化的木聚糖酶组分,分别命名为Xylanase A和Xylanase B。纯化倍数分别为3.58和3.29,回收率分别为7.02%和28.29%。SDS-PAGE结果均为单一条带,分子质量分别为29.6 ku和20.9 ku。酶学性质研究结果表明:Xylanase A和Xylanase B的最适反应温度分别为55℃和60℃;温度低于50℃,两种酶的稳定性都很好;最适pH一样,都为5.0;pH稳定范围也一样,都为3.5~7.0;Mn2+、Tris对Xylanase A有激活作用,Fe2+、Cu2+、SDS则对该酶有抑制作用;Mn2+对Xylanase B有激活作用,Zn2+、Ca2+、Fe2+、Cu2+、Ba2+、Mg2+及SDS则对该酶有抑制作用。

Xylanases from different sources have significant differences in their compositions and properties.In order to develop the industrial applications of xylanase from strain EIM-30,we studied its purification and enzymatic properties.After the crude xylanase from Trichoderma reesei EIM-30 was purified using lyophilization,fractional ammonium sulfate precipitation,Sephacryl S-200 High Resolution gel chromatography and HiTrapTMSP(HP) ion chromatography,two purified xylanases were obtained,which were respectively named as Xylanase A and Xylanase B.Xylanase A was purified about 3.58 times with 7.02% recovery of enzyme activity,and Xylanase B was purified about 3.29 times with recovery of 28.29%.SDS-PAGE showed that the molecular weight of Xylanase A and Xylanase B was 29.6 ku and 20.9 ku,respectively.The enzymatic properties showed that the optimum temperature of Xylanase A and Xylanase B was 55 ℃ and 60 ℃,respectively.The optimum pH of Xylanase A and Xylanase B were both 5.0.When the temperature was below 50 ℃ and the pH was in the range from 3.5 to 7.0,Xylanase A and Xylanase B both exhibited excellent stability.Xylanase A could be enhanced by Mn2 +and Tris,but inhibited by Fe2 +,Cu2 +and SDS.Xylanase B could be enhanced by Mn2 +while inhibited by Zn2 +,Ca2 +,Fe2 +,Cu2 +,Ba2 +,Mg2 +and SDS.