Lignolytic Enzymes and Their Role in the Bioremediation of Environmental Pollutants

Environmental pollutant mitigation using lignolytic enzyme catalysis is an eco-friendly biotechnological approach. The major environmental pollutants present in waste streams include toxic xenobiotics, hydrocarbons (polycyclic hydrocarbons), heavy metals, phenolic compounds (azo dyes), humic substances, and lignin. These pollutants have been biodegraded using various lignolytic enzymes. These lignolytic enzymes are produced by white-rot fungi (WRF). In addition, other microbial species of bacteria, fungi, and haloalkaliphiles produce lignolytic enzymes. The major lignolytic enzymes produced are lignin peroxidase (LiP), manganese peroxidase (MnP), laccase, dye peroxidases, and versatile peroxidase (VP). Lignolytic enzymes mediate bioremediation, transformation, and the degradation of contaminants. They convert them into nontoxic or less toxic, valuable products, which is an eco-friendly process due to the formation of less sludge. Therefore, lignolytic enzymes that catalyze waste streams have a faster conversion rate. However, the microbial conversion of waste streams was prolonged with a lower conversion rate. The enzyme production process is cost-effective. In addition, recalcitrant waste streams require the development of advanced bioprocesses and technology for their treatment. Lignolytic enzymes could be a novel solution to overcome the problem. Therefore, this chapter will discuss the prospects and challenges of various important lignolytic enzymes that are used for the bioremediation of environmental pollutants.