The dsz desulfurization gene cluster from Rhodococcus erythropolis KA2-5-1 was transferred into the chromosomes of Pseudomonas aeruginosa NCIMB 9571 by using a transposon vector. Resting cells of the recombinant strain, PAR41, desulfurized 63 mg sulfur l(-1) of light gas oil (LGO) containing 360 mg S l(-1). The desulfurization activity for LGO by the resting cells of strain PAR41 grown with n-tetradecane (50% v/v) was much higher (10similar to18-fold) than in glucose-grown cells. P. aeruginosa NCIMB 9571 is able to take up water-insoluble compounds from an oil phase which is enhanced by n-alkane.