Biodegradation Characteristics of Heavy Oil by Fungi Isolated from Petroleum Wastewater

Nine fungal strains, previously isolated from produced wastewater in Liaohe oilfield in China, were screened for the study on the biodegradation ability of heavy oil in a batch of shake-flask culture. Among them, fungi F1, F4, F5 and F7 showed relatively higher abilities for the biodegradation of heavy oil. Heavy oil removal rates after 56 days by the above four strains were 57.82 %, 63.30 %, 36.46 % and 45.63 %, respectively. In addition, the biodegradation process followed the first- order kinetics, and the half- life of heavy oil from long to short order was F5>F7>F1>F4. By contrast, fungus F4 was the highest effective strain for heavy oil degradation. Degradation rates of petroleum fractions by different fungal strains varied significantly. And the highest degradation rates of alkanes was 42.99 % by F5, and correspondingly, that of aromatics with 37.87% by F1, and that of colloids and asphaltenes with 46.42% by F4.