Biosurfactants might offer an environmentally friendly solution for tackling oil spills

Newswise — Could biosurfactants potentially enhance microbiological oil degradation in North Sea seawater? A collaborative international research effort involving the universities of Stuttgart, Tübingen, China West Normal University, and the University of Georgia aimed to answer this question. Their findings have unveiled the promising prospects of a more efficient and eco-friendly response to oil spills.

Globally, approximately 1,500 million liters of oil leak into the oceans each year, leading to significant environmental pollution. The presence of hazardous compounds like polycyclic aromatic hydrocarbons in oil poses toxic and mutagenic risks to organisms. Devastating oil spill incidents, such as tanker accidents or mishaps at oil drilling platforms like the Deepwater Horizon in 2010, result in rapid and massive oil releases, compounding the environmental impact.

To combat such oil spills, large volumes of chemical dispersants are commonly applied, ranging in the millions of liters based on the amount of oil. The purpose is to dissolve oil slicks, prevent oil from reaching coastlines, and disperse the oil more effectively in the water. The expectation is that this will enhance microbial oil degradation. Naturally occurring microorganisms with the ability to feed on crude oil components can break them down into harmless substances, effectively cleansing oil-contaminated areas. Biosurfactants may play a crucial role in facilitating this process and improving the overall effectiveness of microbiological oil degradation in North Sea seawater.

According to Prof. Sara Kleindienst, who was affiliated with the University of Tübingen until 2022 and now works at the University of Stuttgart, a 2015 study from the USA yielded surprising results. Contrary to expectations, it demonstrated that chemical dispersants used in deep-sea water from the Gulf of Mexico could actually hinder microbial oil degradation. This finding sparked contentious debates, leaving the question of how to effectively combat oil spills unresolved.

In the pursuit of more environmentally friendly approaches to address oil spills, biosurfactants have emerged as a promising alternative to chemical dispersants. These natural compounds, produced by microorganisms, can enhance the bioavailability of oil components. Consequently, they have the potential to boost microbial oil degradation, which plays a vital role in the purification process. As the quest for effective oil spill responses continues, biosurfactants offer a hopeful avenue for consideration.

Experiments with seawater from the North Sea

Led by environmental microbiologist Professor Sara Kleindienst, an international research team, including geomicrobiologist Professor Andreas Kappler (University of Tübingen) and biogeochemist Professor Samantha Joye (University of Georgia), conducted a comparative study on the effects of biosurfactants and chemical dispersants. To simulate oil spill conditions, the researchers utilized a laboratory setting at the University of Tübingen, where they obtained over 100 liters of surface water from the North Sea near Helgoland.

In their experiment, the seawater was treated with either the biosurfactant rhamnolipid or a dispersant (Corexit 9500 or Slickgone NS), both in the presence and absence of oil. To track the degradation of oil in detail, the team employed radioactive markers. The results were striking. Prof. Lu Lu, who was previously affiliated with the University of Tübingen and is now with the China West Normal University, explained that the oil microcosms treated with rhamnolipid exhibited the highest rates of microbial hydrocarbon oxidation and protein synthesis.

Notably, the impact on the composition of microbial communities differed significantly between the use of biosurfactants and chemical dispersants. Prof. Lu Lu suggests that biosurfactants may stimulate different microbial oil degraders in terms of growth and activity, thereby influencing the cleanup process after oil spills.

Prof. Sara Kleindienst further emphasized the great potential of biosurfactants for future oil spill response in the North Sea or similar nutrient-rich ocean environments. She envisions the development of products based on biosurfactants that offer effective and eco-friendly approaches to combat oil spills.