(640g) Biocatalysis Using Lipase From Pseudomonas Cepacia Immobilized On Functionalized Alumina

Kim, J., University of Cincinnati
Guliants, V. V., University of Cincinnati

Lipase (EC from Pseudomonas cepacia (lipase PS) has high substrate selectivity and catalytic performance under mild conditions, making it ideal for diverse industrial applications. Immobilization of the enzyme provides the advantages of improved stability and reuse. Alumina has high biological and chemical stability, and is a cost-effective enzyme support. Moreover, creating the multipoint interaction between the enzyme and alumina surfaces functionalized by grafting is a highly promising method for enzyme immobilization in practical biocatalysis.

In this study, lipase PS adsorbed on functionalized alumina is employed in the hydrolysis of p-nitrophenyl acetate to investigate the catalytic efficiency and diffusional effects on the immobilized enzyme kinetics. The surface of a commercially available alumina was modified by grafting (3-mercaptopropyl) trimethoxysilane, (3-aminopropyl) trimethoxysilane, or octyltriethoxysilane using a facile neutral solvent, tetrahydrofuran. Functionalization of the surface was confirmed using FT-IR and thermogravimetric analysis. The enzyme activity assay showed that modification of the support surface enhanced the catalytic efficiency and improved external mass-transfer. These effects are attributed to uniform distribution of the immobilized enzyme on the functionalized alumina particles. Lipase PS adsorbed on amine-functionalized alumina showed the highest catalytic efficiency. The biocatalysis of the hydrolysis of p-nitrophenyl acetate at ambient conditions using lipase PS on different functionalized alumina supports has been demonstrated experimentally.