Do Fungal Fuels Foretell Endophytic Future?

Sandia National Lab researchers are zeroing in on production of fuels by endophytic fungi. According to Sandia scientists, the fungi in their lab can break down cellulose directly, and turn it into hydrocarbons.

The fungi grow on cellulose and digest it, forming fuel-type hydrocarbons as a by-product of their metabolic processes. Through genetic manipulation, the Sandia team hopes first to identify these pathways, and then to improve the yield and tailor the molecular structure of the hydrocarbons it produces.

Sandia’s bioscience team is using genetic sequencing to catalog the pathways and other molecular biology techniques to understand how changes in feedstock determine the type and amount of hydrocarbons the fungi make, with a long-term goal of engineering greater quantities of the desirable fuel species.


Meanwhile, Craig Taatjes and John Dec, both engine combustion researchers at Sandia, are experimenting with the main compounds produced by the fungi and are giving feedback to their bioresearch counterparts on the compounds’ ignition chemistry and engine performance. The ideal outcome, Dec said, is to “dial in” the right feedstocks combined with the right set of genes to produce the preferred blend of compounds to go into an engine.

The first step has been to learn what kinds of compounds the fungus makes naturally on its own. “We just don’t know much about some of the compounds, so we need to do research on their ignition chemistry and how they behave in an engine,” Taatjes said. The team, he says, is working with Professor William H. Green at the Massachusetts Institute of Technology to develop an ignition chemistry model that can predict the performance of the classes of compounds made by the fungus.

Hadi and his colleagues are contributing to building up the understanding of the distribution of molecules produced by the various fungi, at which point they can genetically tailor them to produce more of the optimal compounds to suit the needs of engine combustion. _GCC

The scientists and engineers are still working with very small quantities of product, and it will take some time before they will know if the project can be scaled to commercial levels.

Nevertheless, as a research project to expand the boundaries of basic science knowledge of what engineered endophytic fungi can achieve, the approach has potential to seed further projects and perhaps successful industrial ventures.

Endophytes can be injected directly into crops which themselves have been engineered to accept them and provide maximum surface area and biomass for conversion to hydrocarbon -- or any other high value chemical or substance the endophyte's enzymes can produce.

As plants are engineered to grow on marginal soils and to provide higher levels of more convertible biomass, they will provide yet one more piece of the larger interlocking puzzle. For microbial fuels it will take about ten years to proof of feasibility and proof of scalability. Ten more years to scale large enough to capture roughly 10% of the liquid fuels markets -- to microbial fuels alone (not counting alcohols).