Application of lipase immobilized on the biocompatible ternary blend polymer matrix for synthesis of citronellyl acetate in non-aqueous media: Kinetic modelling study

• Compatible ternary blended matrix was made and applied for lipase immobilization.
• Biocatalyst was studied for kinetics of the citronellyl acetate synthesis in detail.
• Immobilized biocatalyst offered fivefold catalytic activity than aggregated lipase.
• Reaction and kinetic studies showed that lipase followed ternary complex mechanism.
• Protocol is recyclable and applied for greener synthesis of various flavour esters.

This work reports the use of new support for immobilization of lipase Burkholderia cepacia (BCL) matrix made up of polylactic acid (PLA), chitosan (CH), and polyvinyl alcohol (PVA). Initially lipase from various microbial sources and immobilization support composition was screened to obtain a robust biocatalyst. Among various biocatalysts preparation, the PLA:PVA:CH:BCL (1:6:1:2) was worked as a robust biocatalyst for the citronellyl acetate synthesis. Various reaction parameters were studied in detail to obtain the suitable reaction conditions for model citronellyl acetate synthesis reaction. Various kinetic parameters such as rmax, Ki(citronellol), Km(citronellol), Km(vinyl acetate) were determined using non-linear regression analysis for the ternary complex as well as bi–bi ping-pong mechanism. The experimental results and kinetic study showed that citronellyl acetate synthesis catalyzed by immobilized lipase BCL followed the ternary complex mechanism with inhibition by alcohol (citronellol). The energy of activation for citronellyl acetate synthesis was found to be lower for immobilized lipase (8.9 kcal/mol) than aggregated lipase (14.8 kcal/mol) enzyme. The developed biocatalyst showed four to fivefold higher catalytic activity and excellent recyclability (up to six cycles) than the aggregated lipase.

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