Improving isobutanol production with the yeast by successively blocking competing metabolic pathways as well as ethanol and glycerol formation.

Background: Isobutanol is a promising candidate as second-generation biofuel and has several advantages compared to bioethanol. Another benefit of isobutanol is that it is already formed as a by-product in fermentations with the yeast , although only in very small amounts. Isobutanol formation results from valine degradation in the cytosol via the Ehrlich pathway.