Scotland’s whisky waste turns into potential car fuel via ancient bacteria

Scotland’s whisky byproducts (draff and pot ale) are being converted into solvents—acetone, ethanol and especially butanol—by the bacterium Clostridium acetobutylicum at Celtic Renewables’ Grangemouth biorefinery, reviving the century-old acetone-butanol-ethanol (ABE) fermentation. Butanol’s energy and chemistry are close enough to gasoline to run in unmodified engines, offering a potential path to scalable, non-crop-based biofuel. The project uses waste whisky feedstock, avoiding food-vs-fuel concerns, and aims to expand to other industry leftovers and higher-value chemicals, though economics and scale remain hurdles as the plant moves from demonstrator to broader production.