Put fungi and bacteria in a pot together and they will compete for resources until one becomes dominant. University of Michigan researchers convinced the T. reesei fungus and E. coli bacteria to coexist, and as a result developed the first biofuel made from fungi and bacteria working together that could also help make sure food stays out of fuel production.
T. reesei is great at breaking down the non-edible parts of plants. The researchers fed it corn stalks and leaves, which it then turned into sugars. They genetically modified E. coli bacteria that then turned the sugars into isobutanol, a biofuel that is safer and more efficient than ethanol. The system produced the highest concentration of biofuel yet that originated from non-edible plant material.
Biofuels are made from biological materials like corn, algae and soy beans, or more exotic materials like tunicates and whiskey byproducts. Ethanol, the most common biofuel, accounts for more than 9 percent of U.S. gasoline. It gives off 67 percent as much heat energy as gasoline when burned, compared to isobutanol’s 82 percent.
But ethanol is made from corn, which means it drives up food costs. Researchers are interested in producing biofuels from non-food materials, such as the corn stalks and leaves used in this case, to avoid that problem. They’re also interested in isolating biofuel in one container instead of a huge manufacturing setup.
“You can put everything in one pot. The capital investment will be much lower, and also the operating cost will be much lower, so hopefully this will make the whole process much more likely to become economically viable,” research lead Xiaoxia Lin said. “We’re hoping that biofuels made in such an efficient way can eventually replace current petroleum-based fuels.”
The Michigan researchers are now working on improving the energy conversion rate, which will lower the cost of producing the fuel. They also need to improve the fungi and bacteria’s tolerance for the toxic fuel. Eventually, they could engineer the bacteria differently to produce other chemicals, such as plastics.