目的：以脂肪酶为催化剂，在有机溶剂中催化月桂酸和植物甾醇合成月桂酸植物甾醇酯。方法筛选出的最佳溶剂为正己烷，最佳的脂肪酶是固定于大孔树脂NKA的假丝酵母脂肪酶（CRL）--固定化酶NKA-CRL。分别以薄层色谱法和气相色谱法为产物定性和定量，以酯化率为考察指标，优选反应温度、酶添加量、底物摩尔比、反应时间等参数。结果在反应温度40℃，酸醇摩尔比2：1，反应时间16 h及酶添加量5%（占底物总质量）的条件下，酯化率达96%，固定化酶NKA-CRL在相同条件下重复催化6次，酯化率仍可维持在80%以上。结论本工艺利用自制的固定化酶，在保证最高转化率的前提下，降低了反应温度，缩短了反应时间，增强了酶的重复利用率。%Objective To synthesize lauric acid phytosterol esters by lipase in organic solvent. Methods It was found that n-hexane was the best organic solvent and the best lipase was immobilized enzyme NKA-CRL (Candida rugosa lipase immobilized on macroporous resin NKA) through screening test. The qualitative and quantitative detections for the product were performed by Thin-Layer Chromatography(TLC) and Gas Chromatography(GC). With esterification rate as an index, the optimization of reaction conditions was studied in detail. Results The optimal conditions were as follows:reaction temperature of 40℃, molar ratio of lauric acid to phytosterol of 2:1, addition of the lipase of 5%and reaction time of 16 h. Under these conditions, the esterification rate reached 96.56%. A yield of more than 80%for phytosterol ester could be obtained with NKA-CRL even after it was used continuously six times. Conclusion With NKA-CRL self-made, this technology can has a better transform rate under the conditions of low reaction temperature, short reaction time and high reuse of lipase.
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