磁性壳聚糖纳米复合材料固定化褶皱假丝酵母脂肪酶催化合成木质甾醇酯

以磁性壳聚糖纳米复合材料共价固定的褶皱假丝酵母脂肪酶为催化剂，以木质甾醇和油酸为原料，对木质甾醇油酸酯的酶法合成工艺条件进行了优化。得到的最佳工艺条件为：催化剂用量12.7%（以底物总质量计），油酸与木质甾醇物质的量比为2∶1，木质甾醇质量浓度为122.9 g/L，反应温度50℃，反应时间24 h。在该条件下，木质甾醇转化率为96.42%。对月桂酸、肉豆蔻酸、棕榈酸不同碳链长度的脂肪酸或混合脂肪酸进行酯化反应，木质甾醇的转化率可达96.67%～98.74%，催化剂使用5次时，转化率仍可达82.45%。

Synthesis of lignosterol oleate catalyzed by Candida rugosa lipase immobilized on magnetic nanocomposites

Using lignosterol and oleic acid as raw materials and Candida rugosa lipase covalently immobilized on magnetic chitosan nanocomposites as catalyst, the conditions for enzymatic synthesis of lignosterol oleate were systematically optimized. Under the optimized conditions of catalyst dosage 12.7% (based on the total mass of substrates), substrate concentration of lignosterol 121.5 g/L, molar ratio of oleic acid to lignosterol 2:1, reaction temperature 50°C, reaction time 24 h, the conversion rate of lignosterol could reach 96.42%. For lauric acid, myristic acid, palmitic acid and mixed fatty acids composed of fatty acids with different chain lengths, the conversion rate of lignosterol could still be as high as 96.67%~98.74%. The immobilized biocatalyst showed good reusability. After being reused for 5 times, the conversion rate of lignosterol could still be obtained in 82.45%.