Growth of the wild-type, boh::tet mutant, bdh::kan mutant, and boh::tet-bdh::kan mutant strains of P. butanovora. The growth substrates were butane and 1-butanol as indicated. Symbols: ▴, wild-type; ▪, boh::tet; ◊, bdh::kan; and •, boh::tet-bdh::kan P. butanovora strains.