Rhamnolipids enhance marine oil spill bioremediation in laboratory system

This paper presents a simulated marine oil spill bioremediation experiment using a bacterial consortium amended with rhamnolipids. The role of rhamnolipids in enhancing hydrocarbon biodegradation was evaluated via GC-FID and GC-MS analysis. Rhamnolipids enhanced total oil biodegradation efficiency by 5.63%, with variation in normal alkanes, polyaromatic hydrocarbons (PAHs) and biomakers biodegradation. The hydrocarbons biodegradation by bacteria consortium overall follows a decreasing order of PAHs > n-alkanes > biomarkers, while in different order of PAHs > biomarkers > n-alkanes when rhamnolipids was used, and the improvement in the removal efficiency by rhamnolipids follows another order of biomarkers > n-alkanes > PAHs. Rhamnolipids played a negative role in degradation of those hydrocarbons with relatively volatile property, such as n-alkanes with short chains, PAHs and sesquiterpenes with simple structure. As to the long chain normal alkanes and PAHs and biomakers with complex structure, the biosurfactant played a positive role in these hydrocarbons biodegradation.

► Rhamnolipids obviously enhanced the oil biodegradation efficiency by 5.6%. ► The hydrocarbons biodegradation follows a order of PAHs > n-alkanes > biomarkers. ► Different order of PAHs > biomarkers > n-alkanes when rhamnolipids was added. ► Another improved rate order by rhamnolipids is biomarkers > n-alkanes > PAHs.