Engineering alcohol tolerance in yeast The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Lam, F. H., A. Ghaderi, G. R. Fink, and G. Stephanopoulos. “Engineering Alcohol Tolerance in Yeast.” Science 346, no. 6205 (October 2, 2014): 71–75. As Published http://dx.doi.org/10.1126/science.1257859 Publisher American Association for the Advancement of Science (AAAS) Version Author's final manuscript Citable link http://hdl.handle.net/1721.1/99498 Terms of Use Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. Title: Engineering alcohol tolerance in yeast Authors: Felix H. Lam1,2, Adel Ghaderi1, Gerald R. Fink2*, Gregory Stephanopoulos1* Affiliations: 1 Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA 2 Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, USA * Correspondence to: G.R.F. (
[email protected]) or G.S. (
[email protected]) Abstract: Ethanol toxicity in yeast Saccharomyces cerevisiae limits titer and productivity in the industrial production of transportation bioethanol. We show that strengthening the opposing potassium and proton electrochemical membrane gradients is a mechanism that enhances general resistance to multiple alcohols. Elevation of extracellular potassium and pH physically bolster these gradients, increasing tolerance to higher alcohols and ethanol fermentation in commercial and laboratory strains (including a xylose-fermenting strain) under industrial-like conditions. Production per cell remains largely unchanged with improvements deriving from heightened population viability. Likewise, up-regulation of the potassium and proton pumps in the laboratory strain enhances performance to levels exceeding industrial strains.