Interfacial activation and bioimprinting of Candida rugosa lipase immobilized on polypropylene: effect on the enzymatic activity in solvent-free ethyl oleate synthesis

Lipase from Candida rugosa adsorbed on polypropylene powder (CR/PP) was subjected to activation pre-treatments in order to enhance its activity in solvent-free ethyl oleate synthesis. The lipase activation achieved upon adsorption onto a hydrophobic support like PP was further enhanced through oil-water interfacial activation and bioimprinting of the immobilized catalyst. Several aliphatic hydrocarbons/buffer pH 7 mixtures were used in the pre-activation of CR/PP with specific activity increments of up to 29%. Molecular bioimprinting was also performed, with specific activity enhancement of near 70% with respect to non-treated CR/PP. The effect of several fatty acids used as templates and the water present in the reaction medium was studied. The oil-water activation and bioimprinting treatments that led to the best activities were assayed at the immobilization step. Instead of pre-treating CR/PP adsorbed in buffer medium, interfacial activation with octane/buffer and bioimprinting with a mix of fatty acids were carried out in the immobilization vial. The best results were found for CR/PP immobilized in 5/95 octane/buffer (v/v, %) medium. In that way, a biocatalyst with enhanced specific activity is obtained right from the immobilization vial with no need of further activation steps prior to reaction.