Immobilization of Burkholderia cepacia lipase on crosslinked chitosan-based support for the synthesis of geranyl acetate

Abstract

Abstract In this study, glutaraldehyde-crosslinked chitosan beads were prepared and characterized for the immobilization of Burkholderia cepacia lipase (BCL, 23,000 U/g). The crosslinking time and the concentration of glutaraldehyde were evaluated. The morphological modifications and the chemical interaction between the chitosan beads and the crosslinking agent were investigated by Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and ninhydrin assay. In general, both the concentration of glutaraldehyde (1.25 and 5.0% v/v) and crosslinking time (6 and 12 h) showed a minor influence on the intensity of the interaction between the crosslinking agent and chitosan. The immobilized BCL was employed in the transesterification of geraniol with vinyl acetate in an organic medium. The effects of the temperature (25–40 °C), reaction time (24–72 h), lipase mass used for the immobilization (20–100 mg) and type of organic solvent were evaluated along with the reusability of the biocatalyst. The lipase (BCL) remained stable and active under mild reaction conditions (35 °C for up to 72 h of reaction). The immobilized lipase showed greater stability in non-polar solvents (log P > 3.0), allowing its reuse, with a gradual loss in the catalytic activity for up to 120 days of storage. The results demonstrated that this immobilization process is efficient and of low cost.