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Nitrosomonas europaea converts aromatic compounds to oxidized products with alkyl ethylbenzenes, halobenzenes and N- and O-containing aromatic substrates. Ammonium sulphate increases the transformation rate as a mechanism-based inactivator of ammonia monooxygenase (AMO). Ring-substituted benzylic alcohol and p-cresol oxidation occur in an AMO-independent manner.

The impact of 15 hydrocarbons and halogenated hydrocarbons on NH3 oxidation by ammonia monooxygenase (AMO) in intact cells of the nitirfying bacterium Nitrosomonas europaea were evaluated. Most inhibitors displayed competitive or non competitive exhibition patterns. AMO activity measured as NO2 production required coupling of hydroxylamine oxidoreductase (HAO) activity with NH3-dependent NH2OH production by AMO. The competitive character decreased as the molecular size of the inhibitors increased. Multichlorinated compounds gave non-linear Limeweaver-Burk plots. Maximum rates of NH3, C2H4 and C2H6 oxidation were roughly equivalent, implying a common rate-determining step.