酸-复合酶法制备玉米芯低聚木糖

Preparation of xylooligosaccharides from corncob by acid-compound enzymes hydrolysis

以玉米芯为原料,用稀酸进行预处理,再利用复合酶水解制备低聚木糖,通过单因素和正交实验确定酸-复合酶法制备玉米芯低聚木糖的最佳工艺。结果表明:酸预处理的最佳条件为:硫酸的浓度为2.5 g/L,在120℃下,玉米芯和稀硫酸按1:6的料液比预处理90 min;复合酶水解的最佳条件为:木聚糖酶和纤维素酶按1:1配比组成复合酶,复合酶的添加量为2%,最适pH为5.0,在50℃下酶解时间为15 min。在该条件下,玉米芯水解液中可溶性总糖为110.24mg/g,还原糖含量为63.72 mg/g,平均聚合度为1.73。

In this study, xylooligosaccharides were obtained by composite enzyme hydrolysis from corncobs, which was pretreated by sulfuric acid. On the basis of single factor and orthogonal test, the preparation process of xylooligosaccharides was studied. Result indicated that the pretreatment of corncobs should be operated at following conditions, 2.5 g/L sulfuric acid concentration, corncobs to acid solution ratio of 1：6, 120 ℃ for 90 min. In addition, the optimal hydrolysis conditions of composite enzyme were determined as 2% composite enzyme containing xylanase and cellulose with the ratio of 1：1, optimal pH 5.0, enzymatic hydrolysis at 50 ℃ for 15 min. Under the optimized conditions, the yield of reducing sugar and total sugar in hydrolysate was 63.72 mg/g of raw corncobs and 110.24 mg/g of raw corncobs, respectively, and the average degree of polymerization was 1.73.