Characterization and optimization of EPS-producing and diesel oil-degrading Ochrobactrum anthropi MP3 isolated from refinery wastewater

Petroleum refinery wastewater (PRW) containing hydrocarbon is highly toxic to the environment and the surrounding ecosystem. Proper treatment of the PRW effluent is necessary to remove the pollutants before discharge. Bioremediation is considered to be a promising approach as it is eco-friendly and efficient. The exopolysaccharide (EPS) produced by the O. anthropi acts as a bioemulsifier and showed the highest emulsification activity of 60% on diesel. An EPS yield of about 0.42 g/L was obtained under optimized conditions. The carbohydrate and protein content of the EPS was found to be 71.1% and 19.7% respectively, showing the glycoprotein nature. The structural properties of EPS were analyzed by FT-IR and ¹H NMR. The batch degradation of oil in PRW by O. anthropi was studied gravimetrically, and showed about 53% degradation in 7 days, indicating the strong ability of the isolated strain to degrade the hydrocarbons in PRW.