MIT engineers have genetically reprogrammed a strain of yeast so that it converts sugars to fats much more efficiently, an advance that could make possible the renewable production of high-energy fuels such as diesel.
The researchers modified the metabolic pathways of yeast that naturally produce large quantities of lipids, to make them about 30 percent more efficient.
This upgrade could make the production of renewable high-energy fuels economically feasible.
Renewable fuels such as ethanol made from corn are useful as gasoline additives for running cars, but for large vehicles like airplanes, trucks, and ships, more powerful fuels such as diesel are needed.
Efforts to develop engines that run on biodiesel made from used cooking oils have had some success, but cooking oil is a relatively scarce and expensive fuel source. Starches such as sugar cane and corn are cheaper and more plentiful, but these carbohydrates must first be converted into lipids, which can then be turned into high-density fuels such as diesel.
To achieve this the researchers began working with a yeast known as Yarrowia lipolytica, which naturally produces large quantities of lipids.
Using their improved pathway, the yeast cells require only two-thirds of the amount of glucose needed by unmodified yeast cells to produce the same amount of oil.
While this new glucose-to-lipid conversion process could be economically feasible at current prices for cornstarch, the researchers are hoping to make the process even more efficient.
