Engineering news
Engineers at the Massachusetts Institute of Technology have genetically reprogrammed a strain of yeast to convert sugars into fats 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% more efficient.
Gregory Stephanopoulos, professor of chemical engineering and biotechnology at the university, said: “We have rewired the metabolism of these microbes to make them capable of producing oils at very high yields.
“What we’ve done is reach about 75% of the yeast’s potential, and there is an additional 25% that will be subject of follow-up work.”
This upgrade could make the production of renewable high-energy fuels economically feasible, as large vehicles such as aircraft, trucks, and ships require more powerful fuels.
Stephanopoulos adds: “Diesel is the preferred fuel because of its high energy density and the high efficiency of the engines that run on diesel. The problem with diesel is that so far it is entirely made from fossil fuels.”
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.
Using this 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.
The researchers are now considering using cheaper sources of plant material, such as grass and agricultural waste, which would require converting the cellulose that makes up those plant materials into glucose.
The study was published in the journal
Nature Biotechnology.