Asphaltene biodegradation using microorganisms isolated from oil samples

► Twenty-five species isolated from oil and polluted soil samples of Dorood oilfield. ► The bacterial mixed culture growth, in a bioreactor was evaluated by CHN and FTIR. ► pH, salinity and asphaltene concentration by B. lentus were optimized using RSM. ► Biodegradation of asphaltene by the mixed culture of five bacteria was 48%. ► Kinetic study showed that the data of asphaltene biodegradation fit to Tessier model.