Fluoranthene, a high molecular weight PAH containing four fused rings, is naturally present in fossil fuels and derivatives thereof, and may be formed during the combustion of carbonaceous materials. To date, there have been no reports of the primary utilization by pure microbial cultures of fluoranthene or of other PAHs containing four or more fused rings. Recently a 7-membered bacterial community isolated from a creosote-waste site was described for its ability to utilize fluoranthene as a sole carbon source. In the paper, a single member of this community is described, isolated in pure culture with the unique ability of utilizing fluoranthene as sole source of carbon and energy for growth. (Copyright (c) 1990, American Society for Microbiology.)