Abstract
The utilization of crude oil by microorganisms isolated from marine environments was investigated. Enrichment procedures for isolating crude oil degrading organisms were carried out using samples of mud collected among the estuaries and along the coast of North Carolina. The basal medium was seawater supplemented with nitrogen and phosphate. The fungi isolated under these conditions utilized crude oil more effectively than did the bacteria and several oil utilizing fungi were isolated in pure culture. Among the fungi selected were strains of Cunninghamella etegans, Aspergillus versicolor, Cephalosporium acremonium, and a Penicillium sp. These fungi utilized a wide variety of hydrocarbon substrates as a source of carbon and energy. All grew on a mineral salts medium with no requirement for seawater.
The amount of crude oil utilized by growing fungi was determined. The results suggested that of the fungi isolated C. elegans and the Penicillum sp. were most effective in degrading crude oil. When paraffin base crude oil was added to the seawater basal salts medium (0.2% v/v) and inoculated with C. elegans over 90% of the oil was assimilated after 5 days growth. Less than oneβhalf of this amount of asphalt base crude oil was utilized. The optimum temperature for growth of fungi that utilized crude oil differed but all grew at temperatures between 15 and 24 Β°C. Significant growth of the fungi on crude oil did not occur unless the seawater was supplemented with a source of nitrogen and phosphorus. The results of this study suggested that fungi can effectively assimilate crude oil and that paraffin base crude is more readily degraded than the asphalt base crude oil.