极耐热性阿拉伯糖苷酶在木糖制备中的应用

阿拉伯糖苷酶作为木聚糖降解的限速酶之一,在植物残体的生物转化、食品加工、饲料工业以及纸浆漂白中具有广泛的应用潜力。实验中选择pET—28a作为表达载体,优化核糖体结合位点RBS与起始密码子ATG间距离,使来自海栖热袍菌(Thermotoga maritima)极耐热性阿拉伯糖苷酶得到高效表达,重组酶蛋白经一步热处理后纯度达到90%以上;木聚糖酶解试验结果表明,阿拉伯糖苷酶和木聚糖酶间存在协同作用;阿拉伯糖苷酶与木聚糖酶和β-木糖苷酶联合水解木聚糖能明显提高酶解产物中木糖含量,因此,开发极耐热性阿拉伯糖苷酶在酶法制备木糖中的应用具有重要的经济效益和社会效益。

Studies on Thermostable α-L-arabinofuranosidase from Thermotoga maritima for the Production of Xylose from Xylan

The thermostableα-L-arabinofuranosidase from Thermotoga maritima was over-expressed in E.coli JM109 (DE3) using the pET28a.The recombinantα-L-arabinofuranosidase was purified by heat treatment to nearly electrophoretic homogeneity for enzymatic production of xylose.Production of xylose from corncob xylan by xylanase,β-xylosidase andα-L-arabinofuranosidase were examined by TLC and HPLC.A synergistic effect of addition ofα-L-arabinofuranosidase to xylanase hydrolysis was confirmed. Much more xylose was produced by xylanase andβ-xylosidase hydrolysis in the presence than in the absence ofα-L-arabinofuranosidase.These results indicate thatα-L-arabinofuranosidase is important in the process of xylooligosaccharides and xylose production.