Twelve strains of Pseudomonas fluorescens and P. putida were grown in a synthetic medium that contained L-lysine as the only source of carbon and nitrogen, and screened for L-lysine-2-monooxygenase production. Best production was by P. putida BKM B-1458 at 30 IU/g wet wt biomass when grown in a shake-flask but 25 IU/g in a 250-l fermenter.