Enzymatic oxidation of 3,4-dihydroxyphenyl-L-alanine (L-DOPA) with laccase from Trametes versicolor was investigated. The highest enzyme activity at pH 5.4 and at 25 ºC was found. The reaction kinetics and the effect of dissolved oxygen concentration on the reaction rate were evaluated. A mathematical model, comprised of double-substrate Michealis-Menten kinetics and mass balances for L-DOPA and dissolved oxygen concentrations, was developed in order to describe and predict the process of L-DOPA oxidation. Kinetic parameters, , and were estimated and experimentally verified by a set of experiments with constant additional aeration for different initial concentrations of L-DOPA and dissolved oxygen. A significant increase in reaction rate was established at a higher oxygen concentration in the inlet gas. The developed model was used to investigate the influence of dissolved oxygen concentration on L-DOPA conversion
