Fungi that Make Fuel Discovered

This Research in Action article was provided to LiveScience in partnership with the National Science Foundation.

"Mycodiesel" is a novel name applied to the volatile organic products made by fungi that have fuel potential. The latest discovery is that of an endophytic Hypoxylon/Nodulosporium species, or one that lives within a plant, that makes the compound cineole along with a number of other cyclohexanes (colorless, flammable liquids found in petroleum crude oil and volcanic gases) and compounds with enormous fuel potential.

Cineole is of special interest since it has been shown that it can be added to gasoline at a ratio of 8 parts cineole to 1 part of gasoline, ending up with a final octane rating of 95. Although yeast makes ethanol by the processes of fermentation, this alcohol is not as energy rich as are other fungal products that have recently been found, such as cineole and the cyclohexanes.

Cineole, having an odor of a eucalyptus tree, had in fact been previously known only from higher plant sources. Now it seems that it can be made by fermentation. Its placement in the market will have to await fungal strain improvement, and other developmental factors needed to optimize its production. In addition, engine testing will be necessary to learn if modifications in design will be needed to handle the new Mycodiesels.

Finally, a close examination of the volatile organic products of a number of endophytic fungi reveals that these products and their related substances are the principal ingredients of regular diesel fuel. Such compounds are the cyclic and straight-chained hydrocarbons such as octane, heptane and cyclohexane followed by the benzene and naphthalene derivatives.

It turns out that many of the compounds found in diesel fuel are either directly found as fungal products or other products that are closely related. This along with a number of other arguments suggests that some or all of the world's crude oil may have originated from microbial sources. Therefore, as the vast amount of organic matter in the world began the processes of decay, the reduced organic products resulting from these processes may have been trapped in the numerous shales of the Earth. It is from these sources that crude oil is mostly recovered.

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