EFFECTS OF THE HERBICIDE MOLINATE ON THE METABOLIC-ACTIVITIES OF A DEGRADATIVE STREPTOMYCES-GRISEUS STRAIN

Cometabolic degradation of the herbicide molinate was tested using two microorganisms, Arthrobacter sp., strain M3 and Streptomyces griseus strain M2; the latter classified on the basis of the presence of the e nzymatic cofactor SF-420. The strains M3 and M2, inoculated in a basic salts medium with glucose as carbon source and added with 100 mg L(-1 ) of molinate, degraded respectively 35 and 51% of the herbicide in 36 days. Increasing concentrations of molinate, ranging from 50 to 200 m g L(-1) in glucose medium, did not affect the final ATP yield ofthe st rain M2, but decreased the final growth yield and the ATP synthesis ra te. Moreover, the onset of coenzyme SF-420 synthesis was progressively delayed. In contrast, surprisingly, SF-420 final yield and production rate were increased by progressive increasing concentrations of molin ate in the mineral medium.