Emprego do octanoato de celulose como suporte para lipases visando a produção de biodiesel

Abstract

Polymers have been used as support for enzymes due to the fact of being able to protect these molecules and to avoid their leaching in the reaction medium with loss of the enzymes with no possibility of later use and the environmental contamination due to the presence of these molecules in industrial waste. In this work, the cellulose octanoate (OC) was produced from microcrystalline cellulose to prepare lipase immobilization systems. This polymer shows a balance of the hydrophilic/hydrophobic character due to the possibility of being produced with different degrees of substitution. This aspect is an important feature in the immobilization of lipases that occur more efficiently in more hydrophobic materials. OC was produced, in a heterogeneous phase, from the reaction of microcrystalline cellulose dispersed in toluene with octanoyl chloride/pyridine. The CO production reaction was accompanied by infrared absorption (FTIR) and nuclear magnetic resonance (NMR) with results showing that the reaction was effective and the degree of substitution (DS) found by 1H NMR was 2.20, which indicates that on average two hydroxyls react per unit glucose in the cellulose. OC presented good solubility in toluene and good film forming ability, which allowed the preparation of the Polymer/Enzyme (OC/E) system by lipase occlusion in the formed film. For the application of this system, the reaction of esterification of oleic acid by free lipase was studied using experimental design. In this study, it was possible to determine the amount of enzyme to be incorporated in the OC film, as well as to define the best amounts of methanol and water for the reaction that was accompanied by FTIR. In the application of the OC/E system, the esterification reaction occurs with low yield. The same condition is observed in reuse. The decrease in the yield of the immobilized enzyme is due to occlusion of the enzyme in the polymer which may have led to a decrease in its enzymatic activity. However, good system stability was observed for later applications. In this way, the system under study has potential for future applications with the improvement of immobilization methods.