异戊酰-L-肉碱在[Bmim]PF_6离子液体中的酶催化合成

Lipase-catalyzed Isovaleryl-L-carnitine Synthesis in [Bmim]PF_6 Ionic Liquid

异戊酰-L-肉碱的酶催化合成需要选择疏水、极性的溶剂作为反应介质。本实验以满足上述条件的离子液体[Bmim]PF6作为反应介质,研究异戊酰-L-肉碱的酶催化合成。其最佳反应条件为:Novozyme 435作为催化剂,初始水分活度0.22,反应温度60℃,异戊酸和L-肉碱摩尔比4:1,反应体系含0.4mmolL-肉碱和1.6mmol异戌酸时,脂肪酶用量50mg,200mg分子筛(反应开始时添加),摇床转速200r/min,反应时间40h。在此条件下产品得率达到59.61%。以[Bmim]PF6为介质的异戊酰-L-肉碱的酶催化合成,其产品得率高于在乙腈中的合成。

To improve significantly the biosynthesis of isovaleryl-L-carnitine catalyzed by lipase needs to select an efficient and suitable reaction medium that is not only polar but also hydrophobic. [Bmim]PF6, which can meet the above two requirements, was applied as the reaction medium in the present study. The effects of 7 key reaction conditions on the biosynthesis of isovaleryl-L-camitine were investigated. The optimal reaction conditions obtained were as follows： Novozyme 435 as the catalyst, initial water activity 0.22, molar ratio of isovaleric acid to L-carnitine 4：1, lipase amount 50 mg （in the reaction system containing 0.4 mmol of L-carnitine and 1.6 mmol of sovaleric acid）, molecular sieve amount （added at the beginning of the reaction） 200 mg, rotation speed of shaking table 200 r/min, temperature 60 ℃, and reaction duration 40 h. Under these conditions, the product yield reached 59.61%, which is higher than that in reaction medium of acetonitrile.