THE ABILITY OF AN ENVIRONMENTAL ISOLATE OF PSEUDOMONAS-FLUORESCENS TOUTILIZE CHRYSENE AND OTHER 4-RING POLYNUCLEAR AROMATIC-HYDROCARBONS

A Pseudomonas fluorescens strain isolated from exhausted-oil-polluted soil was selected for its ability to grow on and degrade chrysene as a sole carbon source. The same strain was able to grow on and degrade b enz[a]anthracene, benzo[b]naphthothiophene, but not benz[a]acridine. A fter 2 days of incubation on a mineral medium supplemented with chryse ne at 1 mu g/ml, reached by adding the Polynuclear aromatic hydrocarbo n dissolved in a water-miscible solvent to the medium, the cell number had increased by 10(2)-10(3). The biodegradation rate followed first- order kinetics and at its maximum value was independent of substrate c oncentration, as happens when the substrates are solubilized.