Laccase mediator system as a potential technology for decolorization of textile dyes — Overview and perspectives

Discharge of the exhausted dye bath at the end of dyeing imposes a huge waste-water load, necessitating the use of freshwater for further processing. Due to the limited availability of fresh water, industries are compelled to remove the dyes fromdrained-out liquor to protect the environment and recycle the treated water for future processing. Discharged dyes create afilm or layer of color on the water's surface, impeding the natural breakdown of substances and harm aquatic organisms.A significant proportion of effluent comprises synthetic dyes from azo, anthraquinone, triphenylmethane, indigo, and othergroups. Several azo dyes and their cleaved by-products have been discovered to impact human health. Various establishedtechniques are commonly employed to remove the color from dye; however, they have inherent restrictions. Due toincreased demand, there is a growing need to explore cost-effective alternative treatments, such as biological integratedsystems. The utilization of laccase for the decolorization of dyes presents a possible technological solution to address thedrawbacks associated with current approaches. These enzymes can chemically react with and break down diversesubstances. Laccases have been verified for their capacity to break down synthetic dyes in wastewater, resulting in thedegradation of less hazardous products than the original dyes. This study examines the advantages and disadvantages ofdifferent technologies used to remove color from dyes. It also discusses the degradation mechanisms of several syntheticdyes catalyzed by laccase and the impact of factors, such as temperature, pH, dye concentration, etc. Additionally, the mostrecent studies on decolorization utilizing laccase are reviewed.