Process design for the oxidation of fluorobenzene to fluorocatechol by Pseudomonas putida

The characteristics of the conversion of fluorobenzene to fluorocatechol by Pseudomonas putida have been determined. Three important constraints on the design of an effective process were identified—reactant inhibition, product toxicity and reactant volatility. The first was overcome by controlled feeding of fluorobenzene to the reactor.

Product toxicity was minimised by the introduction of in situ product removal using a circulation loop from the reactor which contained a packed bed of Norit pK13 onto which fluorocatechol adsorbed. At the end of fed-batch experiments the total amount of fluorocatechol produced was 70 times greater than the minimum toxic level.

A high loss of fluorobenzene from the reactor was eliminated by replacing air sparging by a membrane oxygenator installed in a second loop. The introduction of these two techniques allowed large step changes to be made in the productivity of the biotransformation, making it a much more effective process..