Laccase covalently immobilized on avocado seed biochar: A high-performance biocatalyst for acetaminophen sorption and biotransformation

In this study, the laccase enzyme was immobilized in biochar from avocado seeds and applied to acetaminophen (ACT) sorption and biotransformation. The biochar surface enhanced the bonding capacity between the enzyme and the support after treating it with citric acid and glutaraldehyde. The biochar surface area increased about 12 times after the acid treatment, and carbonyl groups were observed after the treatments. The immobilized laccase demonstrated operational stability for up to seven reuse cycles, maintaining 50.7% of its activity in the biotransformation of ACT. The immobilized enzyme also demonstrated storage stability for 30 days at 4 °C and 25 °C, maintaining more than 90% of its activity in the biotransformation of ACT. This research highlights the use of immobilized enzymes and valorization of agricultural residues for the development of immobilized enzyme systems that are more ecological and sustainable.