Modulation of FAD-dependent monooxygenase activity from aromatic compounds-degrading Stenotrophomonas maltophilia strain KB2

Abstract

The purpose of this study was purification and charac-terization of phenol monooxygenase from Stenotropho-monas maltophilia strain KB2, enzyme that catabolises phenol and its derivatives through the initial hydroxyla-tion to catechols. The enzyme requires NADH and FAD as a cofactors for activity, catalyses hydroxylation of a wide range of monocyclic phenols, aromatic acids and dihydroxylated derivatives of benzene except for cate-chol. High activity of this monooxygenase was observed in cell extract of strain KB2 grown on phenol, 2-meth-ylphenol, 3-metylphenol or 4-methylphenol. Ionic sur-factants as well as cytochrome P450 inhibitors or 1,4-di-oxane, acetone and n-butyl acetate inhibited the en-zyme activity, while non-ionic surfactants, chloroethane, ethylbenzene, ethyl acetate, cyclohexane, and benzene enhanced it. These results indicate that the phenol mo-nooxygenase from Stenotrophomonas maltophilia strain KB2 holds great potential for bioremediation.