Immobilization of lipases on agarose and chitosan and application in biocatalysis

Abstract

Lipases (E.C. 3.1.1.3) are serine-hydrolases which catalyze hydrolysis, esterification and transesterification of acyl glicerides of long chain. Biodiesel, defined as a mix of mono alkyl esters of long chain fatty acid has attracted an increasing interest as a renewable energy source to replace the diesel produced from petroleum. The presented project proposes the study of routes don't investigated for immobilization of lipases techniques from a microbial source, obtained from fungi Acremonium sp, by covalent bonds in modified chitosan with glioxil, epoxy groups and glycidol, and by adsorption on hydrophobic supports, such as phenyl-agarose and octyl-agarose. Immobilized lipases will be compared to commercial lipase Thermomyces lanuginosus, taken as a reference in this work and immobilized under the same conditions. The stability of both immobilized lipases will be evaluated to the pH and temperature. The immobilized lipases will be applied in the transesterification reaction in order to obtain ethyl biodiesel, in which the produced esters will be quantified by gas and liquid chromatography coupled to mass spectrometry. It will also be evaluated the use of ultrasound in the process of biodiesel production, since that form of energy enhances the enzymatic activity. Supports will be characterized as to porosity and surface area, FTIR-ATR, thermal stability by TC and DSC. (AU)