The acetone-butanol fermentation and the closely related 2-propanol-butanol fermentation are of interest to Europe in particular for environmental and socioeconomic reasons, but its economic and technical feasibility must be proven before reestablishment as a commercial proposition. In particular the reestablishment of a new, fledgling fermentation industry selling into markets presently serviced by the mature, firmly established and highly capitalised petrochemical industry will require a significant driving force or else commercial users, who frequently have long-term supply contracts, will remain with known and proven suppliers. Hence the present state-of-the-art of the acetone-butanol fermentation is best described as technically and economically difficult but possible in niche markets. The most likely future is for decentral fermentation facilities processing locally made substrates and selling into niche markets.