木瓜蛋白酶在离子液体双水相中的分配行为

Partitioning behavior and structural characterization of papain in ionic liquid aqueous two-phase system

采用离子液体双水相提取木瓜蛋白酶。首先考察不同浓度、p H、温度的离子液体对木瓜蛋白酶活性的影响,其次考察不同离子液体双水相体系、离子液体侧烷基链长度及浓度、酶添加量、p H、温度对木瓜蛋白酶分配行为的影响。结果表明:[C4mim]Cl和[C4mim]Br体系萃取木瓜蛋白酶的效果比[C4mim]BF4体系好;高温(≥60℃)对离子液体双水相体系萃取木瓜蛋白酶不利。离子液体双水相萃取木瓜蛋白酶的最佳工艺条件:0.25 g·ml-1的[C4mim]Cl,0.35 g·ml-1的K2HPO4,p H 8.0,酶添加量2.0 mg·ml-1,30℃。此条件下木瓜蛋白酶的酶活性回收率达到95.16%,纯化因子达到1.5。为今后进一步研究该体系的放大实验或规模化生产奠定了基础。

Papain was extracted by ionic liquid aqueous two-phase system. Firstly,the influence of concentration, pH, and temperature of ionic liquid on the activity of papain was investigated. Secondly, the effects of different ionic liquid aqueous two-phase systems, alkyl chain lengths and concentrations of the ionic liquid, dosage of papain, pH, temperature on the partitioning behavior of papain were discussed. [C4mim]Cl and [C4mim]Br systems were better than [C4mim]BF4 system in extraction of papain, and it was disadvantageous to extract papain at a high temperature （60℃or higher）. Activity recovery of enzyme reached 95.16%and purification factor reached 1.5 under the optimum conditions：[C4mim]Cl 0.25 g·mL^-1, K2HPO4 0.35 g·mL^-1, pH 8.0, enzyme addition 2.0 mg·mL^-1, 30℃. The result laid the experimental basis for further scale-up research and commercial production.