偏甘油酯脂肪酶Lipase G50的固定化及其催化高酸值米糠油乙酯化脱酸的研究

Immobilization of partial glyceride lipase Lipase G50 and its application in deacidification of high acid value rice bran oil

研究了偏甘油酯脂肪酶Lipase G50的固定化及其催化高酸值米糠油乙酯化脱酸效果。结果表明:相比于其他4种树脂,ECR8285树脂对Lipase G50的固定化效果最好,在载酶量为40 mg/g时,制备得到的固定化Lipase G50的酯化活力为518.66 U/g,比活力为15.65 U/mg;最佳的固定化Lipase G50催化脱酸工艺条件为无水乙醇与高酸值米糠油中游离脂肪酸物质的量比2∶1、酶加量40 U/g、反应温度40℃、反应时间6 h,在最佳条件下高酸值米糠油的酸值(KOH)由62.14 mg/g降至0.12 mg/g;与此同时,固定化Lipase G50在高酸值米糠油脱酸中展现出优异的操作稳定性,连续使用10个批次,酯化活力为509.22 U/g,与初始固定化酶相比,酯化活力没有显著降低。脱酸米糠油经分子蒸馏后,其酸值(KOH)为0.19 mg/g,过氧化值为2.16 mmol/kg,达到了GB/T 19112—2003一级米糠油标准。因此,固定化Lipase G50在油脂脱酸领域具有广阔的应用前景。

The immobilization of partial glyceride lipase Lipase G50 and its catalytic deacidification of high acid value rice bran oil were studied. The results showed that compared with the other four resins, resin ECR8285 had the best immobilization effect on Lipase G50. When the enzyme loading amount was 40 mg/g, the esterification activity and the specific activity of immobilized Lipase G50 were 518.66 U/g and 15.65 U/mg, respectively. The optimal deacidification conditions catalyzed by immobilized Lipase G50 were obtained as follows: molar ratio of ethanol to free fatty acid in high acid value rice bran oil 2∶1, enzyme dosage 40 U/g, reaction temperature 40℃ and reaction time 6 h. Under the optimal conditions, the acid value of high acid value rice bran oil decreased from 62.14 mgKOH/g to 0.12 mgKOH/g. At the same time, immobilized Lipase G50 showed excellent operational stability in the deacidification of high acid value rice bran oil, with esterification activity of 509.22 U/g after 10 batches of continuous use. The deacidified rice bran oil was purified by molecular distillation, and its acid value and peroxide value were 0.19 mgKOH/g and 2.16 mmol/kg, respectively, which reached the standard of first-grade rice bran oil in GB/T 19112-2003. So immobilized Lipase G50 has a promising future in the field of oil deacidification.