Lipase biocatalytic processes in surfactant free microemulsion-like ternary systems and related organogels

摘要

Lipases from Rhizomucor miehei (RmL) and Candida antartcica (CaL-B) entrapped in surfactant free microemulsion-like ternary systems consisting of n-hexane,short chain alcohols (1-propanol or 2-methyl-2-propanol) and water,keep their catalytic activity at 30 deg C,catalyzing efficiently the esterification of fatty acids or natural phenolic acids including cinnamic acid derivatives.High conversions (up to 95%) were obtained with both lipases entrapped in various ternary systems.Lipases catalytic efficiency and stability was influenced by the composition of the ternary systems used.Hydroxypropylmethyl cellulose (HPMC) microemulsions-based organogels (MBGs) formulated with various surfactant free microemulsion-like systems were used as a matrix for enzyme immobilization.These lipase-containing MBGs prove to be a novel solid-phase catalyst for use,under mild conditions,in non-polar solvents as well as in solvent free systems.CaL-B immobilized in surfactant free MBGs keep its catalytic activity for a storage period of 8 months,while the corresponding residual activity of immobilized RmL was decreased by 50%.The stability of enzymes in such surfactant free MBGs is higher than that observed in MBGs formulated with surfactant based w/o microemulsions.Lipases-containing surfactant free MBGs were used in seven consecutive batch syntheses of fatty esters with only 10-15% loss of activity.