Phenol−amine binary system as a facile approach for laccase immobilization and biocatalytic remediation

The mussel-inspired coating offers a sustainable and straightforward method for functionalizing carriers and facile covalent binding of enzymes. The catecholamine groups in dopamine harness the adhesive property, which can be replaced by a phenol-amine chemistry consisting of molecules like tannic acid (TA). To enhance the coating's durability, a silane coupling agent, specifically 3-aminopropyltriethoxysilane (APTES), was utilized to ensure a substantial enzyme loading. In this study, Celite®545 (Cel) is used as a cost-effective support, sequentially functionalized with APTES and TA, to obtain a higher specific surface area enriched with quinone moieties for enzyme immobilization. The TA-functionalized porous support offered up to 50% enzyme immobilization. The temperature and pH-dependent studies indicated an improved activity profile for immobilized laccase compared to free enzyme. Markedly, Cel-APTES-TA@lac could retain enzyme activity of 47% up to 8 cycles and 50% after 15 days when stored at 4 °C. The efficiency of Cel-APTES-TA@lac was investigated for environment remedial applications in the degradation of textile dyes: Reactive red-120 and Orange II in different pH conditions. The laccase immobilized support showed excellent degradation of Reactive red-120 by 91% at pH 3 and Orange II by 79% at pH 5. The work offers a green alternative for biocatalyst binding to readily available silica support for environment remedial applications such as dye degradation.