金针菇菌糠中木聚糖酶的分离纯化及其酶学性质研究

摘要

废弃食用菌栽培料（ SMC）中含有一定活性的木聚糖酶，作者以金针菇菌糠为材料，采用盐析、Sephadex G－100凝胶层析和DEAE C－52离子交换层析等技术，对SMC中的木聚糖酶进行分离和纯化，并进行酶学性质研究。结果表明，该酶经SDS－PAGE电泳鉴定为电泳纯，分子量为37．8 KDa，酶比活力达到946．67 U／mg，纯化倍数为12．74；酶的最适温度和pH分别为50℃和pH 6．0，Fe2＋、Zn2＋对木聚糖酶有激活作用，Ca2＋、Mn2＋、K＋有促进作用，Mg2＋、Cu2＋、Fe3＋有抑制作用，反应动力学参数Vmax和Km 分别为15．43μg／mL／min、9．61 mg／mL。%Xylanase produced by Spent Mushroom Compost was isolated and purified by ammonium sulfate salting-out,Sephadex G⁃100 column chromatography and DEAE C⁃52 anion chromatography exchange,and its enzymatic properties were studied.The results illustrated that it exhibited a single band by the SDS⁃PAGE,and the molecular weight was estimated as 37. 8 KDa. The purification made the specific activity as high as 946.67 U/mg and purification multiple reached 12.74.The optimal temperature and pH value for activity were 50 ℃ and pH 6.0 respectively,which had a certain acid and alkali resistance and high⁃temperature⁃resisting.Xy⁃lanase obtained in this study was activated by Fe2+and Zn2+;promoted by Mn2+,K+and Ca2+;while inhibited by Mg2+,Cu2+ and Fe3+.The Vmax and Km values of the xylanase for xylan were 15.43μg/mL/min and 9.61 mg/mL, respectively.The study suggests that this xylanase has a good potential to be a cold⁃stable xylanase in paper man⁃ufacturing and feed industries.