Effects of Imprinting and Water Activity on Transesterification and Thermostability with Lipases in Ionic Liquid

The effect of bio-imprinting and water activity on catalytic activities and the thermostability of lipases was investigated for transesterification using vinyl acetate and benzyl alcohol as substrates in ionic liquid, [C(n)mim][PF6] (n=4,6,8), and benzene. The catalytic activities were enhanced by imprinting in benzene and [C(4)mim][PF6], and the relations between the transesterification activities and the water activity in both solvents were approximately bell shaped. The reactivity of the transesterification in benzene was higher than that in [C(4)mim][PF6]. The effects of water activity and imprinting on the kinetic parameters in [C(4)mim][PF6] were examined. Without controlling the water content, the values of K-m,K-VA and K-m,K-BA (Michaelis constants of vinyl acetate and benzyl alcohol, respectively) decreased, and the values of V-m (maximum rate) increased by imprinting. On the other hand, by controlling the water content in the organic media, the values of V-m, K-m,K-VA, and K-m,K-BA increased by imprinting. The activities of lipase in ionic liquid are more strongly affected by water activity and imprinting than those in benzene. We observed effects of water activity on thermostability but none from imprinting.

Automated summary

The study found that both bio-imprinting and water activity affect the catalytic activities and thermostability of lipases during transesterification in ionic liquid and benzene. The impact of imprinting and water activity on reaction activity and kinetic parameters varies in different solvents.