Cobaltitas e ferritas na imobilização de lacases de pleurotus ostreatus

Abstract

Laccases are multicopper oxidase enzymes, widely valued for their diverse biotechnological and industrial applications, especially due to their ability to oxidize a wide range of phenolic and non-phenolic substrates. From fungi, plants, and some microorganisms, laccases are particularly abundant in basidiomycete fungi, such as Pleurotus ostreatus, also known as oyster mushroom. Enzymatic purification aims to isolate and concentrate enzymes, involving several techniques and steps, including precipitation with ammonium sulfate. Immobilization of an enzyme is an effective approach to increase enzyme stability and reusability in industrial applications. In this work, laccases produced by the fungus Pleurotus ostreatus were semi-purified and immobilized in spinel-type metal oxides. The enzymes were previously produced by submerged fermentation using residues and co-products from agro-industry and semipurified by the ammonium sulfate method. The supports with a spinel-like structure used to immobilize these enzymes were produced by the citrate-gel method. Immobilization was carried out by adsorption at 25 ºC and 60 minutes. The concentration of 10% (m/v) of ammonium sulfate provided the highest concentration of laccases (70.0 ± 4.55 U/mg). The support that provided the highest enzymatic activity was ZnCo2O4 (34.7 ± 2.71 U/gsupport), followed by NiCo2O4 (29.5 ± 1.32 U/gsupport), showing that cobaltites were more efficient in immobilizing laccases from Pleurotus ostreatus.