超滤和丙酮沉淀法回收纤维二糖水解液中β-葡萄糖苷酶的研究
Recovery of β-Glucosidase from Cellobiose Hydrolysate by Ultrafiltration and Acetone Precipitation
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摘要: 分别利用超滤和有机溶剂沉淀法对纤维二糖水解液中β-葡萄糖苷酶的回收可行性及其工艺进行了研究.利用膜技术回收时,选用截流分子质量30ku膜比较适宜.连续超滤回收不同批次的纤维二糖酶解液中β-葡萄糖苷酶,第1轮的酶回收率和平均膜通量分别为99.6%和118.6L/(m2·h);第20轮回收的β-葡萄糖苷酶为初始加酶量的90%以上,且平均膜通量为79.2L/(m2·h).利用丙酮沉淀回收时,丙酮与纤维二糖水解液的体积比值在0.7~1.0比较适宜;温度和沉淀时间对酶的回收率影响很大.用-20℃丙酮沉淀2h,酶回收率为9.7%,连续沉淀回收不同批次的纤维二糖酶解液中β-葡萄糖苷酶时,第1轮的酶回收率仍能维持在50%左右,可节省所需酶量的79%.Abstract: Feasibility and technology of recovering β-glucosidase from cellobiose hydrolysate by methods of ultrafiltration and acetone precipitation were studied respectively. The 30 ku membrane was selected for recovery of target enzyme when using ultrafiltration technique. From the first batch, β-glucosidase recovery rate and average permeation flux of membrane were 99.6%,118.6 L/(m2·h), respectively. The amount of recovered β-glucosidase from the 20th batch of cellobiose hydrolysate could still be maintained 90% of initial total enzyme activity, and average permeation flux of membrane reached 79.2 L/(m2·h). When acetone precipitation technique was used for recovery, it was suitable to use acetone and cellobiose hydrolysate at volume ratio from 0.75:1 to 1:1. Temperature and precipitation time had great influence on enzyme recovery rate, which was up to 95.7% when using acetone at -20℃ for 2 h. The 50% enzyme activity could still be maintained from the 15th batch of acetone precipitation, which saved 79% amount of the required enzyme.