Dados do Trabalho

Título

Kinetics of lipase-catalyzed synthesis of sugar esters at low pressures

Introdução

The food industry has sought to replace traditional inputs, such as chemical surfactants, with more natural and sustainable alternatives aligned with the principles of the bioeconomy. Sugar esters, highlighted by their biocompatible surfactant properties, have gained prominence in the food, pharmaceutical, and cosmetic sectors.

Material e Métodos

In this study, new sugar esters were synthesized by the enzymatic esterification of glucose with lauric acid, using Novozym435® lipase in systems containing the solvent 2-methyltetrahydrofuran- 3-one (MeTHF-3-one). The reactions occurred in two substrate molar ratios, 6:1 M and 1:1 M of fatty acid to glucose, under low pressure, with a fixed temperature of 60°C and enzyme concentration corresponding to 5% of the substrate mass used. The glucose concentration was maintained at 0.17 M throughout the study. Enzyme kinetics ranged from 2 to 96 hours under agitation at 350 rpm in a temperature-controlled Dubnoff bath (EthikTechnology). The immobilized enzyme was removed by filtration at the end of the reaction. 1 mL samples were taken from the reaction mixture at defined intervals and analyzed by gas chromatography. A control without added lipase was used as a blank for the reaction mixtures.

Resultados e Discussão

The results indicate a greater consumption of lauric acid than predicted by theoretical stoichiometry, suggesting that more than one glucose hydroxyl was esterified, forming different esters. A possible explanation for this behavior is that Novozym 435 lipase, in addition to catalyzing esterification, can catalyze polymerization by opening the ring of ketones, such as lactones. Previous studies have demonstrated the ability of lipases, especially Novozym 435, to catalyze polymerization reactions.

Conclusão

Thus, the enzyme not only promotes the formation of glucose esters but can also facilitate additional reactions involving lauric acid and MeTHF-3-one, resulting in the formation of polymeric products and contributing to the increased consumption of lauric acid observed in the experiments. This study confirms the feasibility of the synthesis of sugar esters through enzymatic esterification of glucose with lauric acid, using Novozym435® lipase in a system with the solvent 2-methyltetrahydrofuran-3-one (MeTHF-3-one), providing valuable insights for the development of more sustainable and efficient processes in the food, pharmaceutical, and cosmetic industries.