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

Abstract

The purpose of this study was purification and characterization of phenol monooxygenase from Stenotrophomonas maltophilia strain KB2, enzyme that catabolises phenol and its derivatives through the initial hydroxylation 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 catechol. High activity of this monooxygenase was observed in cell extract of strain KB2 grown on phenol, 2-methylphenol, 3-metylphenol or 4-methylphenol. Ionic surfactants as well as cytochrome P450 inhibitors or 1,4-dioxane, acetone and n-butyl acetate inhibited the enzyme activity, while non-ionic surfactants, chloroethane, ethylbenzene, ethyl acetate, cyclohexane, and benzene enhanced it. These results indicate that the phenol monooxygenase from Stenotrophomonas maltophilia strain KB2 holds great potential for bioremediation.

Stenotrophomonas maltophilia: A Gram-Negative Bacterium Useful for Transformations of Flavanone and Chalcone

“…The isolation, purification, and analysis of genetic and biochemical properties revealed that the S. maltophilia KB2 strain contains enzymes belonging to oxygenases: phenol monooxygenase [ 28 ] and catechol 2,3-dioxygenase [ 29 ]. Phenol monooxygenase is the enzyme that takes part in the key step of phenolic compound decomposition.…”

“…The maximum activity of the enzyme occurs at pH 7.2 and a temperature of 30 °C. The activity of the monooxygenase of the KB2 strain is associated with the cytochrome system [ 28 ].…”

Toxicity and biodegradation of ibuprofen by Bacillus thuringiensis B1(2015b)

“…The activity of monooxygenase and catechol 1,2-dioxygenase was observed in the crude extracts from each monosubstrate culture (Table 1). The higher activity of monooxygenase in the presence of ibuprofen, phenol and benzoate reveals hydroxylation, the first step of aromatic compound degradation (Wojcieszyńska et al 2011b), while the activity of catechol 1,2-dioxygenase indicates ortho cleavage of the aromatic ring of these compounds (Guzik et al 2013). In the presence of 4-hydroxybenzoate as an inductor, the activity of monooxygenase and catechol 1,2-dioxygenase was significantly lower than in the control culture with glucose (Table 1).…”

Over-the-Counter Monocyclic Non-Steroidal Anti-Inflammatory Drugs in Environment—Sources, Risks, Biodegradation

“…Two of the most important enzymes involved in salicylate decomposition are salicylate 1-hydroxylase and salicylate 5-hydroxylase (monooxygenases). Salicylate monooxygenases belong to one of the three groups of hydroxylating oxygenases—activated-ring monooxygenases (Wojcieszyńska et al 2011 ). The general structure of these groups includes a three-component protein with separate functional units: reductase with a flavin cofactor, ferrodoxin with a Rieskie-type iron-sulfur cluster [2Fe-2S] and hexamer-built α 3 β 3 terminal oxygenase with [2Fe-2S] a cluster and one nonheme iron(II) per α subunit (Mason and Cammack 1992 ; Bertini et al 1996 ).…”