Sunday, April 29, 2007

Optimal activities of lipase entrapped in sol–gel determined by the response surface methodology

Rubiani C. Pinheiro1, Cleide M. F. Soares2, Heizir F. de Castro3, Onelia A. A. Santos1, Flavio F. Moraes1, and Gisella M. Zanin1. (1) Chemical Engineering Department, State University of Maringa, Av. Colombo, 5790, BL E-46, Maringa, 87013-190, Brazil, (2) Instituto de Tecnologia e Pesquisa, Universidade Tiradentes, Av. Murilo Dantas, 300, Farolandia, Aracaju - SE, 49032-490, Brazil, (3) Engineering School of Lorena, University of São Paulo, P.O.Box 116, Lorena - SP, 12602-810, Brazil

The conditions for maximizing the enzymatic activity of lipase entrapped in a sol-gel matrix were determined for different vegetable (canola, soybean and olive) oils, using experimental design. The effects of pH (X1), temperature (X2) and biocatalyst loading (X3) on immobilized lipase activity were verified using a central composite experimental design, leading to a set of 13 assays with various combinations of experimental conditions and the results were processed by the surface response analysis. For canola and soybean oils, statistical analyses showed significant effects for all variables and also for the interactions between pH and temperature (X1.X2) and pH and biocatalyst loading (X1.X3). For the olive oil, it was verified that the pH was the only variable statistically significant. This study demonstrated that the response surface analysis is a methodology quite adequate for maximazing the percentage of hydrolysis, as a function of pH, temperature and lipase loading.