DEGRADATION OF HYDROCARBONS IN CRUDE-OIL BY THE ASCOMYCETE PSEUDALLESCHERIA-BOYDII (MICROASCACEAE)

Four unique strains of Pseudallescheria boydii were isolated from oil- soaked soils in British Columbia and Alberta and compared to strains f rom cattle dung and raw sewage. Considerable variability in morphology , colony appearance, colony diameter, and temperature tolerance occurr ed among the strains. They also varied in the sporogenous states produ ced in culture; all strains had a Scedosporium anamorph and either the Graphium anamorph or cleistothecial teleomorph. Conspecificity of the six isolates was inferred from their morphology and supported by rest riction fragment length polymorphism profiles of the internally transc ribed spacer region of rDNA and comparing these to Petriella sordida, a similar taxon in the Microascaceae. Three of the strains isolated fr om oil-contaminated soil and the strain from sewage were tested for th eir ability to utilize hydrocarbons by incubation with Prudhoe Bay Cru de oil as the sole carbon source. Gas chromatographic analysis of the residual oil revealed that the strains isolated from oil-contaminated soil degraded the linear aliphatics. The strain from sewage, previousl y shown by others to utilize the volatile n-alkanes (i.e., ethane, pro pane, and butane), did not utilize the liquid saturate compounds. None of the strains was observed to degrade compounds in the aromatic frac tion. Pseudallescheria boydii may be an important agent for in situ bi oremediation of saturates in oil-contaminated sites.