凝胶涂层包覆大孔树脂固定化脂肪酶的制备及在风味酯合成中的应用

Immobilization of lipase on macroporous resins followed by gel-coated and its application for synthesis of flavour esters

风味酯是一种重要的香料化合物,在食品、化妆品和制药等行业具有重大的应用价值。酶法合成风味酯具有反应条件温和、选择性高以及污染少等优点,但在有机溶剂中,游离脂肪酶的活性会有极大的损失。为了提高脂肪酶的稳定性,该研究首先使用大孔树脂通过吸附作用固定化脂肪酶,然后对酶蛋白表面进行丙烯酰化修饰和聚合反应,在固定化脂肪酶的表面形成凝胶涂层的包覆。此种方式制备的固定化脂肪酶稳定性有了较大提高。利用该固定化酶分别通过酯化反应合成乙酸丁酯和转酯反应合成乙酸异戊酯,结果显示,以正庚烷为溶剂,乙酸和丁醇浓度均为0.1 mol/L,并添加1 g固定化酶,在45℃经过12 h的反应,乙酸丁酯的合成率达到93.05%,重复利用4次后仍然有70.83%的酯合成率;在3 mL乙酸乙烯酯溶液中加入0.8 mol/L异戊醇和0.5 g固定化酶,在45℃经过14 h的反应,乙酸异戊酯的合成率达到92.35%,重复利用4次后仍然有84.80%的酯合成率,研究建立了一种固定化脂肪酶的新方法,并为风味酯的制备奠定了基础。。

Flavour esters are significant fragrance compounds with substantial applications in the food,cosmetic and pharmaceutical industries.Enzymatic synthesis of flavour esters catalyzed by lipase has the advantages of mild reaction conditions,high selectivity and minimal pollution.However,the activity of free lipase can suffer significant losses in organic solvents.In order to enhance the stability of lipase,the study first immobilized lipase on macroporous resins through adsorption,followed by acrylation modification and polymerization reaction on the surface of the enzyme protein to form a gel coated encapsulation.The stability of the immobilized lipase prepared in this way was greatly improved.Subsequently,the immobilized enzyme was employed to synthesize butyl acetate and isoamyl acetate through esterification and transesterification reactions,respectively.The results showed that using n-heptane as the solvent,with both acetic acid and butanol at 0.1 mol/L,and adding 1 g of the immobilized enzyme,the synthesis rate of butyl acetate reached 93.05%after 12 h of reaction at 45℃,and it still maintained a 70.83%ester synthesis rate after four cycles of reuse.In a 3 mL solution of vinyl acetate,with 0.8 mol/L isoamyl alcohol and 0.5 g of the immobilized enzyme,the synthesis rate of isoamyl acetate reached 92.35%after 14 hours of reaction at 45℃,and it still had an 84.80%ester synthesis rate after four cycles of reuse.This research established a novel method for immobilization of lipase,which laid a foundation for the preparation of flavor esters.