Immobilized Laccase: A Promising Bioremediation Tool for the Removal of Organic Contaminants in Wastewater

Abstract

Laccase, an incredible enzyme, has a wide prospective in bioremediation processes, mainly due to its relative broad oxidation capacity, the lack of requirement of cofactors, and the use of readily available oxygen as the final electron acceptor. However, the large-scale application of laccases in bioremediation necessitates immobilization/insolubilization of the biocatalysts to enhance their operational stability. With the burgeoning use of laccases in wastewater treatment, several state-of-the-art methods have been developed over the past few years to immobilize laccase, derived from various microbial sources, in order to enhance the selectivity, activity, stability, and reusability. Recent advances in these immobilization methods offer promising solutions to the limitations of soluble enzymes, such as poor reusability due to poor recoverability, low stability, and high costs, to name a few. This article is intended to review the various recent methods employed for immobilization or insolubilization of laccase and its use in treating various types of organic contaminants in wastewaters including those from olive mill, pulp and paper, biorefinery, municipal, hospital, and textile industries. Furthermore, to improve the potential of the laccase-based biocatalytic system against wastewater/pollution treatment, co-immobilization of enzymes such as tyrosinase, peroxidase, and glucose oxidase, with laccase, would serve as a promising bioremediation tool for treating the organic contaminants in industrial and municipal wastewater. The concept and approach of this review also renders knowledge on a yet unexplored focus on the pioneering advances on the development of immobilized laccase-based reusable biocatalysts, which could be employed for treatment of industrial and hospital wastewater.