Engineered yeast chummy with ethanol

Here's a foamy welcome to an engineered yeast that can consume more sugar to make more alcohol, and still get up for work the next day. This new strain of yeast and the technique to make it, reported by Gregory Stephanopoulos and his colleagues at MIT, have potential applications in everything from biofuel production to medicine (Science 2006, 314, 1565). Typically, yeast can't withstand ethanol concentrations greater than about 10% by volume, which limits the amount of ethanol that can be produced in one run in a large fermentor. The researchers, however, used a novel approach to improve the yeast's viability in ethanol concentrations of up to 20%. Instead of trying to evolve the many genes involved in yeast glucose metabolism or in protection from ethanol damage, they engineered the basic transcriptional machinery that translates the genetic code into proteins. Three mutations in a protein that helps direct RNA polymerase to DNA had a ubiquitous impact on the expression of more than 100 genes, leading to the improved production and tolerance of ethanol.