Oxytetracycline Removal in a PLA-Immobilized Laccase Bioreactor: Experimental Evaluation and Diffusion–Convection–Reaction Modeling

This work presents a novel integrative approach to the design and computational modeling of a bioreactor system for the enzymatic removal of antibiotics from aquatic environments. The study focuses on a three-dimensional mathematical model developed to resolve the diffusion–convection–reaction dynamics within the system. Programmed in MATLAB R2025a, the model integrates theoretical equations to determine the diffusion and convection coefficients, while the reaction rate constant was precisely determined through the experimental degradation data of oxytetracycline. To support this modeling, laccase was covalently immobilized on a chemically modified polylactic acid (PLA) matrix, achieving a 95.6% immobilization yield. Simulation results revealed that the system is primarily governed by the convection constant and that degradation efficiency is significantly optimized by reducing the reactor’s internal diameter. These findings demonstrate that the coupling of theoretical transport phenomena with experimentally derived kinetics provides a high-resolution tool for predicting bioreactor performance. By combining biocatalysis, materials science, and computational modeling, this research offers a scalable and environmentally friendly solution with direct implications for the development of advanced water treatment technologies.