Influence of the physico-chemical characteristics of the hybrid matrix on the catalytic properties of sol-gel entrapped Pseudomonas fluorescens lipase

Abstract

Lipase from Pseudomonas fluorescens (Amano AK) was immobilized using the sol-gel entrapment technique and sol-gel entrapment combined with adsorption on a solid support (Celite 545). The sol-gel matrices were obtained using as precursors ternary mixtures of tetramethoxysilane and trimethoxysilanes substituted with phenyl or vinyl groups, at different molar ratios, and 1-octyl-3- methyl-immidazolium tetrafluoroborate as additive. The obtained enzymatic preparates were efficient biocatalysts in the acylation reaction of racemic secondary alcohols. Several methods were employed for the characterization of the resulting bioactive materials, in order to correlate the catalytic performance with the morphological and physico-chemical properties of the matrix: Fourier transform infrared spectroscopy (FTIR), BET-analysis of specific surface and porosity, laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM), atomic force microscopy (AFM) and thermogravimetric analysis (TGA). An extensive study attested the excellent temperature stability and reusability of the immobilized lipases, thus indicating their possible utilization in industrial applications.