Bioremediation of industrial effluents by ligninolytic microbes

Lignin is a complex biopolymer which forms the hard part of woody tissues. It’s high molecular weight and rigid nature makes it recalcitrant for digestion. Lignin is exudated to access other compounds like cellulose, hemicellulose etc., for industrial production of bioethanol, paper etc., Paper pulp industries being one of the major wood processers remove lignin through various thermochemical methods like sulphonation, chlorination etc., to give a soft texture for paper. The resulting effluents are rich in recalcitrant lignin derivatives which pollutes the receiving water bodies making it toxic to aquatic life. Bioremediation is the use of biological agents like microorganisms to break down environmental pollutants. The biodegradation of lignin can be carried out by microbes such as bacteria and fungi which possess lignin degrading enzymes like Lignin peroxidase (LiP), Manganese peroxidase (MnP), Laccase. Ligninolytic enzymes have bioremediation potential to degrade the industrial effluents and other xenobiotic wastes. In this study the ligninolytic bacteria were studied for the presence of ligninolytic enzymes and were tested for application in bioremediation by analyzing their potential in reducing Chemical Oxygen Demand (COD) of industrial effluents. The isolates showing effective reduction could be exploited for bioremediation.