Nanopartículas magnéticas de cobalto na imobilização de lipases

Abstract

Biological catalysts, such as lipases, have emerged as an alternative to chemical catalysts due to the current concern for environmental protection. Lipases have gained prominence in catalytic studies because they are versatile and act in various reactions such as hydrolysis and synthesis. Its ability to convert vegetable oil to methyl esters or another short-chain alcohol ester in a single transesterification reaction, combined with the need for biofuel production, has drawn attention to its use in biodiesel production. However, its application is disadvantaged by the high costs. Some alternatives for cost reduction are the use of agroindustrial residues for the production of this enzyme, besides immobilizing it in a low cost support that allows easy recovery and gives greater stability to the enzyme when compared to the free form. With this in mind, this work aimed to test the efficiency of cobalt magnetic nanoparticles, with and without celite, as support for lipase immobilization through factorial design and to use the biocatalyst obtained in the hydroesterification reaction for biodiesel production. In this work, the lipase used was produced by the Botryosphaeria ribis EC-01 fungus by submerged fermentation in media containing soybean cake and glycerol as substrate in previously optimized condition. The enzymes produced were immobilized on the supports by adsorption. Supports with cobalt magnetic nanoparticles were produced efficiently, proven by their remarkable magnetic capacity. High lipase activities were obtained on both supports and the maximum (1527 U / gNPS + EC) predicted by the model can be achieved using a temperature of 34 ºC and a time of 27 minutes. The morphological analyzes of the material suggest that the immobilized enzymes are organized in clusters, interacting mainly with the nanoparticles. Infrared analyzes showed the characteristic bands of celite material and enzyme, showing that the enzyme was immobilized. The biocatalyst made from celite-free cobalt nanoparticles provided the best conversion to esters (20%), also evidenced by the acidity index test. The results obtained in this work proved that the cobalt magnetic nanoparticles with and without celite are effective supports for the immobilization of lipases, constituting a biocatalyst that is easy to recover and capable of hydroesterifying fatty materials for the production of fatty acid esters. Future studies will be employed to increase the cover rate