Abstract: The present invention relates to methods for making recombinant thermophilic bacteria of the family Bacillaceae. In particular, recombinant thermophilic Bacillaceae are provided which have been engineered to produce butanol and/or butyrate. Preferably, heterologous nucleic acid molecules encoding one or more butanol or butyrate biosynthetic pathway enzymes are introduced into a thermophilic Bacillaceae in order to produce a recombinant thermophilic Bacillaceae which is capable of producing butanol. The Bacillaceae is preferably of the genus Geobacillus or Ureibacillus. The invention also relates to a method of producing butanol using the Bacillaceae of the invention.