DEGRADATION OF PYRENE BY MYCOBACTERIUM-FLAVESCENS

A strain of Mycobacterium flavescens was isolated from polluted sedime nts. It was capable of utilizing pyrene as a sole source of carbon and energy. When pyrene was supplied as a suspension at 50 mu g/ml, the g eneration time was 9.6 h and the rate of pyrene utilization was 0.56 m u g ml(-1) day(-1). In addition to pyrene, the strain could mineralize phenanthrene (17.7%) and fluoranthene (17.9%), but failed to minerali ze naphthalene, chrysene, anthracene, fluorene, acenaphthene and benzo [a]pyrene, as determined by recovery of radio-labeled CO2 in incubatio ns conducted for 2 weeks under growth conditions. Metabolites produced during growth on pyrene were detected and characterized by HPLC and G C-MS. The product of initial ring oxidation, 4,5-dihydroxy-4,5-dihydro pyrene was identified, as well as ring-fission products including 4-ph enanthroic acid, phthalic acid, and 4,5-phenanthrenedioic acid.