Caracterizaciones Lac-NPMs

Abstract

Laccases are extensively studied by researchers because they can efficiently catalyze phenolic and non-phenolic compounds, as well as extremely recalcitrant environmental pollutants such as textile dyes. Between all carriers available for enzymatic immobilization, magnetic nanoparticles have the advantage of easy bioseparation by an external magnetic field from the reaction medium. Cobalt ferrite magnetic nanoparticles were synthesized and functionalized to immobilize laccases produced by Phlebia brevispora BAFC 633. The functionalization was made with 3-aminopropyltriethoxysilane followed by glutaraldehyde. The biocatalyst was employed to bioremove thymol blue from an aqueous solution. Magnetic nanoparticles were characterized by FTIR, TEM, DRX and magnetism, before and after immobilization. Immobilized laccases removed 86% of thymol blue in 23 h, and showed the same bioremoval capability even 3 cycles. The Michaelis-Menten constant was determinate, and immobilized laccases exhibit higher affinity to thymol blue and 2,6-dimethoxyphenol than free laccases. Regarding stability, immobilized laccases kept 78 % of activity at 28 days while it was maintained in the refrigerator against free laccases, which reached 63 % of initial activity at 28 days under the same conditions. The effective concentration 50 from Lactuca sativa was near 100 % when the effluent was diluted at least 1:1 in water. Thus, the biocatalyst obtained has a potential approach in the bioremoval and detoxification of dyes such as thymol blue.