 Isobutanol can be a better biofuel than ethanol due to its higher energy density and lower hygroscopicity. The branch chain structure of isobutanol gives a higher octane number than the isomeric endbutanol. Sacramuses cerevisiae was chosen as the production host because of its tolerance to alcohols and robustness in industrial fermentations. This article was authored by Kahumal Kaisa, Keeland-Brant Morton C, Borodina Irina, and others.