This Thematic Issue on biobutanol, edited by Michael Sauer, is dedicated to the 100th anniversary of the first industrial exploitation of Chaim Weizmann’s acetone-butanol-ethanol fermentation process. Major aspects of industrial microbiology are exemplified by this single process. This includes new technologies like the latest developments in metabolic engineering, the exploitation of biodiversity and discoveries of new regulatory systems such as for microbial stress tolerance, as well as technological aspects like bio- and down-stream processing.