Screening And Molecular Characterization Of Polycyclic Aromatic Hydrocarbons Degrading Yeasts

Objective: Disasters such as leakages and accidental falls are the main causes of environmental pollution by the petroleum industry product. Since no commercial yeast strain with biodegradation capacity is available, we aimed to isolate and characterize hydrocarbon degrading yeasts.Methods: Yeast isolates used in the study were isolated from samples of wastewater, active sludge and crude oil, which was obtained from a petroleum refinery as well as from soil samples, which were contaminated with crude oil. Yeast isolates used in the study were isolated from wastewater, active sludge and petroleum samples obtained from petroleum refinery and soil samples contaminated with petroleum. Degradation of naphthalene, phenanthrene, pyrene and crude petroleum by yeasts were determined using a microtiter plate-based method. Molecular characterization was achieved by performing a sequence analysis of the ITS1-5.8S rRNA-ITS2 and 26S rRNA regions.Results: In total, 100 yeast isolates were obtained from four different samples. Following the incubation in media containing different polycyclic aromatic hydrocarbon compounds (naphthalene, phenanthrene, pyrene) and crude petroleum, 12 yeast isolates were detected to degrade more than one polyaromatic hydrocarbon. Sequence analyses of rRNA regions revealed that the identified yeasts represented 10 species belonging to 6 genera. The isolates were identified as Candida parasilopsis, Candida sinolaborantium, Cryptococcus albidus, Cryptococcus diffluens, Cryptococcus uzbekistanensis, Pichia kudriavzevii, Rhodosporidium diobovatum, Rhodotorula glutinis, Rhodotorula muciloginosa and Saccharomyces cerevisiae.Conclusion: Yeast strains that are capable of degrading more than one polycyclic aromatic hydrocarbon compound have the potential of being utilized in future research.