Abstract:

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.

Key words: ionic liquid, aqueous two-phase system, papain, activity recovery of enzyme, purification factor, extraction, protein

摘要：

采用离子液体双水相提取木瓜蛋白酶。首先考察不同浓度、pH、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、pH、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, pH 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。

关键词: 离子液体, 双水相, 木瓜蛋白酶, 酶活性回收率, 纯化因子, 萃取, 蛋白质