Laccase-Mediated Bioremediation of Dye-Based Hazardous Pollutants

Abstract

Increasing urbanization and uncontrolled development of textile ameni- ties together with the dearth of efficient removal and/or treatment strategies led to discharge wastewater effluents loaded with various toxic, recalcitrant, and oncogenic dyes. Mostly, such hazardous pollutants are being excluded into main water streams either with or without partial and/or incomplete treatments. Owing to the techno- economic restrictions, several of in practice chemical/physical routes are either inef- ficient or deterring. Enzyme-assisted bioremediation is an easy, eco-sustainable, and widely pursued approach to biodegrade and biotransform a range of organic contam- inants and recalcitrant xenobiotic compounds. Laccases have demonstrated great bioremediation potential owing to their excellent catalytic efficiency and high chemo-, regio-, and enantio-selectivity under slight environmental settings. Enzyme immobilization increases the half-life, catalytic efficiency, and thermal steadiness of the enzymes. Several techniques extending from simple reversible adsorption and ionic bonding to the irreversible covalent attachment have been employed to immo- bilize laccase onto various support materials. These engineering strategies create immobilized biocatalyst of variable catalytic stability and reusability attributes by manipulating the surface microenvironment of the carrier support. In this chapter, an effort has been made to address laccase immobilization (carrier-supported as well as carrier-free immobilization) as a futuristic eco-friendlier and practical choice for the abetment of dye-based effluent wastewater by appraising its physicochemical proper- ties and catalytic performance. The concluding remarks, current challenges, and future scenarios for the remediation of dyes are also discussed. Keywords