Bioremediation of marine oil spills by immobilized oil-degrading bacteria and nutrition emulsion

The combination of bioaugmentation and biostimulation was used to speed up the bioremediation of marine oil spills. A novel carrier material that consisted of puffed panicum miliaceum (PPM), calcium alginate and chitosan was prepared. The porous structure and low density of PPM ensured this carrier material not only had appropriate physical and biological properties for the aggregation of microorganisms but also was biodegradable and floating on the seawater surface for bioremediation of oil pollution. An oil-degrading bacterial consortium was immobilized via adsorption on the carrier material. The immobilized bacteria were observed with scanning electron microscopy. The number of viable cells immobilized on the material was approximately 1.12 × 108 CFU/g. To solve the problem of nutrients supplementation in seawater, an emulsion formed with urea solution, soybean lecithin, alcohol and oleic acid was prepared as oleophilic fertilizer. The results from laboratory and field mesocosm experiments showed that the combination of immobilized bacteria and the emulsion achieved a higher oil removal efficiency compared with the use of them separately. The results of field mesocosm experiments conducted in the coastal seawater showed that most of the petroleum pollutant (> 98%) was removed from the surface of seawater in 24 h. GC–MS analysis showed that most components of petroleum pollutants had been removed. This formula with immobilized bacteria and emulsion can be exploited further for the bioremediation of marine oil spills.