DEGRADATION OF DICLOFOP-METHYL BY PURE CULTURES OF BACTERIA ISOLATED FROM MANITOBAN SOILS

Pure cultures of Chryseomonas luteola and Sphingomonas paucimobilis is olated from Manitoban soils were able to utilize diclofop-methyl (meth yl-2-[4-(2,4-dichlorophenoxy)phenoxyl propanoate) as the sole source o f carbon and energy. An actively growing culture of C. luteola complet ely degraded 1.5 mu g diclofop-methyl . mL(-1) to diclofop acid and 4- (2,4-dichlorophenoxy)phenol within 71 h, as determined by gas chromato graphic analysis. The accumulation of these metabolites in the growth medium resulted in the cessation of growth, indicating the organism's inability to degrade phenoxyphenol in the presence of diclofop acid. S phingomonas paucimobilis mineralized 1.5 mu g diclofop-methyl . mL(-1) to diclofop acid within 54 h. A biphasic growth pattern indicated tha t this organism was capable of degrading diclofop acid to 4-(2,4-dichl orophenoxy)phenol and 2,4-dichlorophenol and (or) phenol. Neither of t he organisms was able to utilize 2,4-dichlorophenol as the sole source of carbon and energy.