MIT scientists report that they have engineered yeast that can improve the speed and efficiency of ethanol production. Currently used as a fuel additive to improve gasoline combustibility, ethanol is often touted as a potential solution to the growing oil-driven energy crisis. But, according to the MIT team, there are significant obstacles to producing ethanol. One is that high ethanol levels are toxic to the yeast that ferments corn and other plant material into ethanol.
By manipulating the yeast genome, the researchers have engineered a new strain that can tolerate elevated levels of both ethanol and glucose, while producing ethanol faster than unengineered yeast.
The key to the MIT strategy is manipulating the genes encoding proteins responsible for regulating gene transcription and in turn controlling the repertoire of genes expressed in a particular cell. These types of transcription factors bind to DNA and turn genes on or off, essentially controlling what traits a cell expresses.
The traditional way to genetically alter a phenotype organism is to alter the expression of genes that affect the phenotype. But for traits influenced by many genes, it is difficult to change the phenotype by altering each of those genes, one at a time. Targeting the transcription factors instead can be a more efficient way to produce desirable traits, note the MIT scientists.
“It is the makeup of the transcripts that determines how a cell is going to behave and this is controlled by the transcription factors in the cell,” says Dr. Stephanopoulos.