ABSTRACT
A local yeast isolate named A was isolated from polluted area of Abou-Qir gulf (Alexandria, Egypt), identified according to a partial sequence of 18sRNA as Candida tropicalis. The isolate showed a high potency in petroleum oil biodegradation as well some hydrocarbons. Morphological changes in cell diameter of this yeast were recognized upon growing the target cell in sea water medium supplemented with petroleum oil as sole carbon source in comparison to the growth in enriched medium. Statistically-based experimental design was applied to evaluate the significance of factors on petroleum oil biodegradation by this yeast isolate. Eleven culture conditions were examined by implementing Plackett-Burman factorial design where aeration, NH4Cl and K2HPO4 had the most positive significance on oil degradation.