新型固定化Aspergillus oryzae脂肪酶催化合成1,3-二油酸-2-棕榈酸甘油三酯

Catalytic preparation of 1,3-dioleoyl-2-palmitoylglycerol by a novel immobilized Aspergillus oryzae lipase

旨在评价自制固定化sn-1,3专一性脂肪酶Aspergillus oryzae L03(AOL)替代商业固定化脂肪酶酸解法合成1,3-二油酸-2-棕榈酸甘油三酯(1,3-dioleoyl-2-palmitoylglycerol,OPO)的可行性。以棕榈硬脂和油酸为原料,在正己烷体系中,得到AOL最适反应参数为:反应温度55℃,反应时间1 h,棕榈硬脂和油酸的底物摩尔比为1∶8,正己烷与底物混合物质量比1∶6,AOL水分含量3.5%(w/w)。该条件下,OPO含量44.9%,三棕榈酸甘油酯(PPP)含量为3.23%,sn-2位棕榈酸占所有棕榈酸比例为68.86%,符合国家标准。同时,AOL和LipozymeRM IM、LipozymeTL IM两种商品酶对比,AOL的催化速率最快,1 h达到最大OPO生产峰值。经过8次循环使用,AOL具有良好的操作稳定性。研究表明,自制的新型廉价固定化酶AOL具有良好的应用前景。

This study aimed to evaluate the potential value of a novel immobilized sn-1,3 selective lipase Aspergillus oryzae L03（ AOL） as a feasible alternative to the commercial lipases for synthesis of 1,3-dioleoyl-2-palmitoylglycerol（ OPO）. The optimal conditions of AOL-catalyzed acidolysis of palm stearin with oleic acid in n-hexane system were obtained as follows： temperature was 55 ℃,reaction time was 1 h,substrate molar ratio was 8（ mol / mol）,hexane and substrates mate ratio was 1∶ 6,and AOL water content was 3. 5%（ w / w）. Under these conditions,the contents of OPO and PPP were 44. 9% and 3. 23%,respectively. And the proportion of palmitic acid（ PA） at sn-2 position to total PA was 68. 86%. All data conformed to the national standard. At the same time,the catalytic rate of AOL was the fastest and it reached the largest OPO yield in 1 h compared with commercial lipases Lipozyme RM IM and Lipozyme TL IM. AOL was stable after consecutively operation for eight times. The results showed that the newly cheaper immobilized lipase AOL had a good application prospect.