O uso do glicerol para a obtenção de produtos de alto valor agregado via biocatálise

Abstract

Eversa® Transform 2.0 is a lipase derived from Thermomyces lanuginosus produced by a genetically modified microorganism. It has a low production cost, high substrate specificity, and high catalytic activity in organic synthesis. Glycerol is a subproduct of the biodiesel industry, and in this research, glycerol is used to produce glycerides. The Taguchi method was used to evaluate the best conditions for the enzymatic esterification of glycerol with acetic acid. A yield of 84.8% was obtained, under the optimal conditions (temperature = 40 ◦C; molar ratio glycerol/acid = 1:1; biocatalyst = 15% w/w; time = 12.5 h). After the statistical analysis, the temperature was found to be the most significant parameter influencing the reaction conversion. A theoretical study was carried out to generate a homology model of the enzyme, based on other natural lipases. Molecular docking, molecular dynamics, and QM/MM simulations were applied to understand the mechanism of esterification and to derive thermodynamic and kinetic data. The nucleophilic attack step was identified as the rate-limiting step for both acylation (13.1 kcal/mol) and deacylation (13.8 and 12.9 kcal/mol) reaction mechanisms. Although the enzyme is capable of esterifying all three alcohol groups of glycerol, the esterification of the primary alcohols is thermodynamically more favorable (5 kcal/mol), especially at higher temperatures.