BACTERIAL-DEGRADATION OF LOW CONCENTRATIONS OF PHENANTHRENE AND INHIBITION BY NAPHTHALENE

Phenanthrene-degrading bacteria were isolated from enrichment cultures of soils contaminated with creosote and jet fuel, The isolates from t he creosote enrichments were classified by fatty acid methyl ester pro files as Acidovorax delafieldii and Sphingomonas paucimobilis; the bac terium from the jet fuel-contaminated soil was not identified and was designated strain JFD 11. All three isolates used phenanthrene as a so le carbon and energy source, and two of the isolates used fluoranthene as a sole carbon and energy source, Anthracene and fluorene were come tabolized by all three strains, but pyrene was not transformed, Naphth alene inhibited all of the strains, and 28-h cultures of A. delafieldi i were inhibited by naphthalene concentrations as low as 5 ppm, Short- term degradation experiments were undertaken with center-well flasks a nd concentrations of phenanthrene ranging from 1.2 to 12.0 mu M. Since initial degradation rates were not a function of phenanthrene concent ration, it was inferred that the half-saturation constants were less t han the lowest phenanthrene concentration tested.