Nanostructured reversed micelles induce a high laccase activity in organic solvents, because enzymes can maintain their highly dimensional structure in water pools of reversed micelles [RMs]. Laccase attracts considerable attention as a novel industrial enzyme due to its high capability to catalyze the oxidation of aromatic compounds. The catalytic activities of lyophilized laccase and laccase entrapped in RMs were compared using an oxidative reaction. Laccase hosted in an anionic RM effectively catalyzed the oxidative reaction in various organic solvents, while lyophilized laccase exhibited no such catalytic activity. To optimize the preparation and reaction conditions for laccase in RMs, we examined the effects of pH of water pools of RMs, the concentrations of both enzyme and surfactant for the preparation of RMs, the hydration ratio (Wo), and the reaction temperature on laccase catalytic activity in organic media. Laccase entrapped in RMs exhibited the highest catalytic activity in isooctane under the following conditions: bis-2-ethylhexyl sulfosuccinate sodium salt (AOT) of 100 mM, pH 6.0, Wo=40, and reaction temperature of 60 degreesC. Under the optimum conditions, environmental pollutants such as bisphenol A, 2,4-dichlorophenol and 2,4,6-trichlorophenol were effectively degraded in 3 h.