Fungus Fights Air Pollution By Removing Sulfur From Crude Oil

The finding could help reduce air pollution and acid rain caused by the release of sulfur components in gasoline and may help oil companies meet tougher emission standards for fuel, the scientists say.

Their study is scheduled for the Oct. 1 issue of ACS' Industrial & Engineering Chemistry Research, a bi-weekly journal.

Jalal Shayegan and colleagues point out that existing processes for refining so-called "heavy," or high-sulfur, crude oil convert sulfur to hydrogen sulfide gas at high temperatures and pressures. However, they leave behind some kinds of sulfur-based compounds, which wind up in gasoline and other fuels. Scientists long have known that certain microbes can remove sulfur from oil. But nobody had tried using these microbes in so-called biodesulfurization of heavy crude oil until now, they indicate.

In the new study, the scientists describe isolation and testing of the first fungus capable of removing sulfur from heavy crude oil. The fungus, called Stachybotrys, removed 65-76 percent of the sulfur present in certain heavy crude oil from two different oil fields. The process does not need high temperatures and high-energy consumption because it occurs slightly above room temperature, they scientists note.