Antibiotics derived from a mutant of Bacillus circulans.

A mutant of Bacillus circulans, which produces butirosins only when 2-deoxystreptamine is added to the fermentation medium, was employed in the biosynthesis of antibiotics containing modified aminocyclitols. The blocked mutant converted 2,5-dideoxystreptamine into 5-deoxybutirosamine. Streptamine was incorporated into a complex differing from butirosin by an additional hydroryl at C-2.