酵母发酵结合酶法纯化石莼功能性低聚糖

Purification of Ulva lactuca functional oligosaccharides by yeast fermentation combined with enzyme

采用酵母发酵结合酶法纯化石莼功能性低聚糖.以蛋白脱除率、低聚糖保留率和低聚糖含量为指标,探讨影响石莼功能性低聚糖脱蛋白、去除游离糖的主要因素,并采用U_(10)~*(10~8)拟水平均匀试验设计优化其关键工艺参数.结果表明,酵母发酵结合酶法纯化石莼功能性低聚糖的最佳工艺条件组合为:酵母接种量7%、发酵时间4.0 h、酸性蛋白酶使用量250 U·g^(-1)、酶解液pH 4.0、酶解温度45℃,同时结合150 r·min^(-1)的摇床转速、30℃的发酵温度、2.5 h的酶解时间,所得纯化后的石莼功能性低聚糖样液中的低聚糖含量从其粗品的(5.00±0.04)%下降为(3.37±0.02)%,蛋白脱除率为(68.5±0.37)%.在此纯化条件下,石莼功能性低聚糖的纯度为81%.

Yeast fer^nentation combined with enzyme was adopted to purify Ulva lactuca functional oligosaccharides. Major factors in-fluencing protein and free sugar removal rates were deter^nined through single factor experiment, with protein removal rate, retention and concentration of oligosaccharides being indicators. Then, U1（）（ 108） quasi-level of unifor^m design experiment was employed to op-timize the key process parameters. The results indicated that the optimum technological condition was to inoculate 7 % yeast and add 250 U ？ g ＇acid protease and to hydrolyze at pH 4.0 under 45 丈 for 4.0 h. Subsequently, the hydrolysate was fermented at a shaking speed of 150 r · min-1 under 30 丈 for 2.5 h. In the end, the concentration of U.lactuca functional oligosaccharides declinded from （5.00±0.04） % to （3.37± 0.02） %, with protein removal rate reaching （68.5 ±0.37）%. After being purified, the purity of U.lactuca functional oligosaccharides was 81% .