A team led by a Montana State University professor has found a fungus that produces a new type of diesel fuel, which they say holds great promise. Calling the fungus' output "myco-diesel," Gary Strobel and his collaborators describe their initial observations in the November issue of Microbiology.
The discovery may offer an alternative to fossil fuels, said Strobel, MSU professor of plant sciences and plant pathology. The find is even bigger, he said, than his 1993 discovery of fungus that contained the anticancer drug taxol.
Strobel, who travels the world looking for exotic plants that may contain beneficial microbes, found the diesel-producing fungus in a Patagonia rainforest. Strobel visited the rainforest in 2002 and collected a variety of specimens, including the branches from an ancient family of trees known as "ulmo." When he and his collaborators examined the branches, they found fungus growing inside. They continued to investigate and discovered that the fungus, called "Gliocladium roseum," was producing gases. Further testing showed that the fungus -- under limited oxygen -- was producing a number of compounds normally associated with diesel fuel, which is obtained from crude oil.
"These are the first organisms that have been found that make many of the ingredients of diesel," Strobel said. "This is a major discovery."
Strobel is the lead author of the paper published in Microbiology. His MSU co-authors are Berk Knighton and Tom Livinghouse in the Department of Chemistry/Biochemistry, and Katreena Kluck and Yuhao Ren in the Department of Plant Sciences and Plant Pathology. Other co-authors are Meghan Griffin and Daniel Spakowicz from Yale University and Joe Sears from the Center for Lab Services in Pasco, Wash.
Strobel doesn't know when drivers will fill their gas tanks with fungi fuel or if processors can make enough to fill the demand. The road to commercialization is filled with potential glitches, he said. It's also a major endeavor that will be left to others who specialize in those areas.
Myco-diesel could be an option for those who want alternatives even to ethanol, however, Strobel said. Some car manufacturers who shun ethanol might consider myco-diesel or fuels produced by other microbes.
"The question is, are there other microbes out there that can do for us?" he asked.
Researchers in government agencies and private industry have already shown interest in the fungi. A team to conduct further research has been established between MSU's College of Engineering and researchers at Yale University. One member of the team is Strobel's son, Scott, who is chairman of molecular biophysics and biochemistry at Yale and a Howard Hughes Medical Institute Professor. The MSU-Yale team will investigate a variety of questions, including the genetic makeup of "Gliocladium roseum."
"The main value of this discovery may not be the organism itself, but may be the genes responsible for the production of these gases," Gary Strobel said."There are certain enzymes that are responsible for the conversion of substrates such as cellulose to myco-diesel."
Scott Strobel said his team is already screening the fungus' genome. Besides determining the complete genetic makeup of the fungus, they will run a series of genetic and biochemical tests to identify the genes responsible for its diesel-making properties.
"The broader question is, what is responsible for the production of these compounds," Scott Strobel said. "If you can identify that, you can hopefully scale it up so you end up with better efficiency of production."
Scott Strobel said he agrees with his father that the discovery is exciting.
There's nothing in the scientific literature about a microbe that produces the diversity of medium-chain hydrocarbons found in the "Gliocladium roseum," he said. Longer hydrocarbon chains are common, but "that's not what you put in your gas tank or jet engine."
Another promising aspect is that the fungus can grow in cellulose.
"That's the most common organic molecule on earth," Scott Strobel said. "It's all around us, everywhere."
Scientists in a variety of disciplines should be able to work together to optimize production and find a way to turn what is essentially a vapor into a burnable, liquid fuel, he added.
- Strobel et al. The production of myco-diesel hydrocarbons and their derivatives by the endophytic fungus Gliocladium roseum (NRRL 50072). Microbiology, 2008; 154 (11): 3319 DOI: 10.1099/mic.0.2008/022186-0
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