Researchers have discovered a new strain of bacteria that can produce non-toxic, comparatively inexpensive “rhamnolipids,” and effectively help degrade polycyclic aromatic hydrocarbons (PAHs) – environmental pollutants that are one of the most harmful aspects of oil spills.
Because of its unique characteristics, this new bacterial strain could be of considerable value in the long-term cleanup of the massive Gulf Coast oil spill, scientists say. More research to further reduce costs and scale up production would be needed before its commercial use, they added.
The findings on this new bacterial strain that degrades the PAHs in oil and other hydrocarbons were just published in Biotechnology Advances, by researchers from Oregon State University and two collaborating universities in China. OSU is filing for a patent on the discovery.
“PAHs are a widespread group of toxic, carcinogenic and mutagenic compounds, but also one of the biggest concerns about oil spills,” said Xihou Yin, a research assistant professor in the OSU College of Pharmacy.
“Some of the most toxic aspects of oil to fish, wildlife and humans are from PAHs,” Yin said. “They can cause cancer, suppress immune system function, cause reproductive problems, nervous system effects and other health issues. This particular strain of bacteria appears to break up and degrade PAHs better than other approaches we have available.”
The discovery is strain “NY3” of a common bacteria that has been known of for decades, Pseudomonas aeruginosa. It was isolated from a site in Shaanxi Province in China, where soils had been contaminated by oil.
P. aeruginosa is widespread in the environment and can cause serious infections, but usually in people with health problems or compromised immune systems. However, some strains also have useful properties, including the ability to produce a group of “biosurfactants” called rhamnolipids.
A “surfactant,” technically, is a type of wetting agent that lowers surface tension between liquids – but we recognize surfactants more commonly in such products as dishwashing detergent or shampoo. Biosurfactants are produced by living cells such as bacteria, fungi and yeast, and are generally non-toxic, environmentally benign and biodegradable. By comparison, chemical surfactants, which are usually derived from petroleum, are commonly toxic to health and ecosystems, and resist complete degradation.
Biosurfactants of various types are already used in a wide range of applications, from food processing to productions of paints, cosmetics, household products and pharmaceuticals. But they also have uses in decontamination of water and soils, with abilities to degrade such toxic compounds as heavy metals, carcinogenic pesticides and hydrocarbons.
