New bacteria could help clean up oil spill

A new strain of bacteria has been found that could help clean up some of the nastiest pollutants in the massive Gulf oil spill.

The bacterium can produce non-toxic, comparatively cheap ‘rhamnolipids’, which help degrade polycyclic aromatic hydrocarbons (PAHs) – pollutants that are one of the most harmful aspects of oil spills.

Oregon State University 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. “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 called Pseudomonas aeruginosa. It was isolated from a site in Shaanxi Province in China, where soils had been contaminated by oil.

P. aeruginosa is widespread, and can, rarely, cause serious infections. However, some strains also have useful properties, including the ability to produce a group of biosurfactants called rhamnolipids.

But the researchers say that NY3 has an ‘extraordinary capacity’ to produce rhamnolipids that could help break down oil and degrade  PAHs.

Because rhamnolipids are non-toxic and completely biodegradable, they offer compelling advantages over their synthetic chemical counterparts made from petroleum, say the researchers.

“The real bottleneck to replacing synthetic chemicals with biosurfactants like rhamnolipid is the high cost of production,” Yin said. “Most of the strains of P. aeruginosa now being used have a low yield of rhamnolipid. But strain NY3 has been optimized to produce a very high yield of 12 grams per liter, from initial production levels of 20 milligrams per liter.”

NY3 is easy to grow and cultivate, and might be available for commercial use in a fairly short time, says the team, adding that by using low-cost sources of carbon or genetic engineering techniques, it may be possible to cut costs even further and scale up production.