双水相木聚糖酶水解体系制备木二糖及其纯化

摘要

Xylobiose was prepared by xylanase hydrolysis of birchwood xylan in the PEG6000/sodium citrate aqueous two-phase system ( ATPS) . The optimized conditions for enzymatic hydrolysis in ATPS were birchwood xylan 10 g/L, xylanase 20 IU /g (calculated by the mass of xylan), 50 ℃ and pH 5. 6. The enzymatic hydrolysis yield of xylobiose was 13. 8% for 8h. The recoveries of xylanase and xylobiose were 66. 4% and 87. 2%, respectively. Then, purification of xylobiose was carried out on Sephadex LH-20 with using degassed high purified water as eluent. The optimized conditions for purification of xylobiose were column temperature 35 ℃, 0. 1 mL/min and sample volume 0. 3 mL. After purification, the purity of xylobiose was improved to 98. 5% under the optimized conditions.%采用聚乙二醇6000/柠檬酸钠的双水相木聚糖酶水解体系制备木二糖，以10 g/L桦木木聚糖为底物，木聚糖酶的酶用量为20 IU/g(以木聚糖质量计)，在50℃、pH值5.6条件下，水解8 h制备木二糖，木二糖的酶解得率为13.8%。双水相水解体系对木聚糖酶回收率为66.4%，对木二糖回收率为87.2%；采用凝胶层析纯化方法，以葡聚糖凝胶LH-20为分离介质，脱气超纯水为洗脱剂，在柱温35℃、洗脱溶剂流速0.1 mL/min、上样量0.3 mL条件下，分离纯化木二糖，木二糖纯度为98.5%。