泡盛曲霉β-1，3-1，4-葡聚糖酶的纯化、性质及其用于制备β-葡寡糖

Purification and Characterization of a β-1，3-1，4-Glucanase from Aspergillus awamori and Its Application in Preparation of Glucooligosaccharides

摘要:

作者研究了泡盛曲霉（Aspergillus awamori）一种β-1，3-1，4-葡聚糖酶（AaBglu29）的纯化、性质及其水解燕麦麸皮制备葡寡糖。粗酶液采用硫酸铵沉淀、QSFF强阴离子柱和DEAE-52弱阴离子柱层析3步纯化，得到电泳级纯酶，经SDS-PAGE和Sephacryl-100测定的相对分子质量分别为30.7×103和27.6×103。该酶最适pH为5.0，最适温度为55 ℃。AaBglu29底物特异性专一，对大麦葡聚糖、燕麦葡聚糖和地衣多糖的比酶活力分别为9 500、7 950 U/mg和5 980 U/mg。该酶水解燕麦麸皮产生葡三糖和葡四糖，经优化，当底物质量分数为5%，加酶量为100 U/g时，于50 ℃、pH 5.0条件下水解4 h，葡寡糖转化率可达90%。AaBglu29优良的酶学特性使其在食品和饲料工业具有较大的应用潜力。

Abstract:

A β-1，3-1，4-glucanase（AaBglu29） from Aspergillus awamori was purified and its application in glucooligosaccharides production from oat bran was studied. The β-1，3-1，4-glucanase was purified to homogeneity by ammonium precipitation and anion-exchange chromatography. The molecular mass of AaBglu29 was estimated to be 30.7×103 and 27.6×103 by SDS-PAGE and gel filtration，respectively. The AaBglu29 was most active at pH 5.0 and 55 ℃. The enzyme displayed strict substrate specificity towards barely β-glucan（9，500 U/mg），oat β-glucan（7 950 U/mg） and lichenan（5 980 U/mg）. In addition，the enzyme was suitable for production of glucooligosaccharides（GOS） from oat bran. The highest GOS yield of 90%（based on β-1，3-1，4-glucan in oat bran） was achieved from 5% oat bran after 4 h of enzymatic hydrolysis（100 U/g） at 50 ℃ and pH 5.0. The properties indicated that AaBglu29 is a promising candidate for application in food and feed fields.