Tuesday, April 20, 2010
10-08

Multipoint covalent immobilization of lipase on chitosan hybrid hydrogels: Influence of polyelectrolyte complex type and chemical modification on catalytic properties of the biocatalysts

Adriano Aguiar Mendes1, Paulo Waldir Tardioli1, Enrique Jose Mammarella2, Dasciana S. Rodrigues1, Roberto C. Giordano1, Heizir F. de Castro3, and Raquel L. C. Giordano1. (1) Chemical Engineering Department, Federal University of Sao Carlos, Washington Luiz, Km 235, Monjolinho, Sao Carlos, SP, Brazil, (2) Institute of Technological Development for Chemical Industry, National University of Litoral, Santa Fe, Argentina, (3) Engineering School of Lorena, University of São Paulo, P.O.Box 116, Lorena - SP, 12602-810, Brazil

This work aimed to produce stabilized derivatives of Thermomyces lanuginosus lipase (TLL) through multipoint covalent immobilization of the enzyme on chitosan based matrixes, activated with different methods. Selected derivatives were tested in the catalysis of biodiesel synthesis by ethanolysis of palm oil. Chitosan was used in a pure form or as polyelectrolyte complexes (PEC) with κ-carrageenan, gelatin, alginate and polyvinyl alcohol (PVA). The hydrogels were chemically modified with 2,4,6 trinitrobenzene sulfonic acid (TNBS) to increase the support hydrophobicity aiming at the improvement of the support properties for lipase immobilization. The modified support was activated with glycidol (GLY), epichlorohydrin (EPI) or glutaraldehyde (GLU). The chitosan-alginate polyelectrolyte chemically modified with TNBS allowed obtaining derivatives with the highest apparent hydrolytic activity (HAapp.) and thermal stability, 45-fold more stable than the soluble lipase. The maximum immobilized enzyme loading (17.5 mg protein.g-1 of gel) was obtained after activation with glutaraldehyde and offering 50 mg protein.g-1 of gel. The kinetic properties of these best derivatives were further determined. The temperature for maximum hydrolysis activity shifted from 60°C, for the soluble lipase to 65-70°C after immobilization, for all the Chitosan-Alginate-TNBS lipase derivatives. Similar pH profiles were observed for soluble and the tested lipase derivatives. TLL immobilized in chitosan-alginate-TNBS activated with the epoxyde reactants (GLY and EPI) led to the highest yield when catalyzing the ethanolysis of palm oil to produce fatty acid ethyl esters, reaching 100 % of conversion in 48 h.

See more of Poster Session Two
See more of General Submissions

See more of The 32nd Symposium on Biotechnology for Fuels and Chemicals (April 19-22, 2010)