Production of 3-nitrocatechol by oxygenase-containing bacteria: optimization of the nitrobenzene biotransformation by Nocardia S3

Twenty-one microorganisms were screened for their ability to convert nitroa romatics into 3-nitrocatechol as a result of the action of an oxygenase. Cu ltures containing toluene dioxygenases and phenol monooxygenases accumulate d 3-nitrocatechol during incubation with nitrobenzene and nitrophenol, resp ectively. Nocardia S3 was selected and studied in more detail. Toluene-preg rown cultures were able to degrade nitrobenzene with a concomitant formatio n of 3-nitrocatechol. The rates of nitrobenzene utilization decreased throu ghout the biotransformation period and finally the accumulation ceased. The gradual deterioration of the biotransformation rates was not a consequence of depletion of the NADH pool, but was due to the accumulation of 3-nitroc atechol. The inhibition of nitrobenzene biotransformation by 3-nitrocatecho l greatly impacts 3-nitrocatechol production processes.