Covalent immobilization on chitosan of ligninolytic enzymes obtained from Ganoderma parvulum and their application in the biodegradation of acetaminophen

Water quality is essential to maintain human well-being and the balance of ecosystems. A subclass of organic chemicals that are being detected with increasing frequency in water bodies have been classified as emerging pollutants; Among them, pharmaceutical products are under special attention because they have biological activity and some of high consumption, as acetaminophen, are being released in large quantities into the environment causing damage. Due to this, various methods and techniques have been developed and studied to degrade contaminants. Fungi have drawn particular attention, and among them, the most promising and studied are white-rot fungi, thanks to their ligninolytic enzymes. Although free enzymes have applicability, research on immobilized enzymes is of great industrial interest, due to the fact that they can be used for more than one catalytic cycle. Initially, enzyme production was carried out cultivating Ganoderma parvulum in a 5L bioreactor. Subsequently, the enzymes were partially purified and covalently immobilized on chitosan microspheres. It was found that among the parameters evaluated, the best immobilization efficiency was obtained with 10% glutaraldehyde, 60 minutes of crosslinking time and 10,000 U/L of laccase. In addition, the operational stability of the microparticles with enzymes and their application in the biotransformation of emerging contaminants such as acetaminophen were evaluated. Finding up to 98% biosorption/biotransformation of acetaminophen associated with immobilized enzymes after four hours of reaction, results that are sought due to the ubiquitous presence of these drugs in nature and their toxicological properties in the environment.