Removal of petroleum‐crude oil from aqueous solution by Saccharomyces cerevisiae SHSY strain necessitates at least an inducible CYP450ALK homolog gene

Abstract

Petroleum crude-oil (PCO) components are known to be mutagenic or carcinogenic, and their contamination in soil and aquifer is of great environmental concern. PCO could be degraded by bacteria, fungi, and yeast. In yeast, the family CYP52 (P450ALKs) of Cytochrome P450 was described as n-alkane-degrading enzymes. In this study, we isolated a new strain SHSY of Saccharomyces able to grow on hydrocarbons compounds. Morphological and molecular characterization led to identify the isolated yeast SHSY as a Saccharomyces cerevisiae. SHSY strain had a remarkable ability to tolerate a high concentration of PCO and use it as a carbon source. A significant relationship was established between the increase in biomass (42.46 ± 1.01-fold) and the disappearance of the crude oil (72.34%) in an aqueous solution. A 690-bp amplicon corresponding to a high conserved region of known CYP450ALK genes was amplified in the genomic DNA of SHSY strain. The sequence of the amplified fragment shared a high identity (71.8%) with CYP52A3 gene of Pichia stipites. The expression of CYP52A3 homolog gene was induced and the expression of both InoP2/InoP4 transcription factor genes in SHSY was stimulated in the presence of PCO. The identified strain SHSY of S. cerevisiae presents an interesting model to minimize the mixed toxicity of PCO in polluted environmental sites.