Desenvolvimento e otimização de biocatalisadores imobilizados por modificação química de suportes ativados: estudo da estabilidade e atividade enzimática

Abstract

Enzyme immobilization is a strategy that aims to provide improvements in some characteristics such as stability, selectivity and specificity, as well as recovery and reuse of enzymes. With this, this work aims at the development and optimization of

biocatalysts through immobilization protocols through the chemical modification of pre-existing supports. The supports activated with divilsulfone (DVS) proved to be useful for the stabilization of enzymes via multipoint covalent bonding, due to the moderate hydrophobicity of the vinylsulfone groups, which conditions the formation of a heterofunctional support, capable of interacting with the protein by physical adsorption or through the covalent bond. The enzyme penicillin G acylase (PGA) from Escherichia coli was immobilized on heterofunctional supports of different chemical nature, with the vinylsulfone group as a constituent part of these. For this purpose, the steps related to the immobilization process were optimized in order to improve the stability and enzymatic activity of the produced biocatalysts. Through the use of the different variables related to the immobilization steps, PGA showed stability similar to that of glyoxyl-agarose-PGA, considered one of the most stable biocatalysts of this enzyme. In addition to this work, a study was carried out on the stability of the lipases Candida antarctica (forms A and B), Thermomyces lanuginosus (TLL) and Candida rugosa (CRL), immobilized through different protocols, in the hydrolysis of substrates of different nature, through conditioning from biocatalysts to stress inactivations. The possibility of change in stability as well as enzymatic specificity are strongly influenced by the experimental conditions in which they will be inserted. Finally, the lipase A biocatalysts of Candida antarctica were investigated through their application in the synthesis of geranyl butyrate aroma, via the enzymatic route. Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Fluorescence (XRF) analysis were used to evaluate the coverage of supports and immobilized structures as well as the chemical composition of these samples.