Bacitracin production by the high-yielding mutant Bacillus licheniformis strain AL: stimulatory effect of L-leucine.

The high-yielding mutant Bacillus licheniformis AL produced only small amounts of bacitracin in the chemically defined M2 medium. L-leucine markedly stimulated bacitracin production and restored the mutant strain to its place as a superior producer as compared to Bacillus licheniformis ATCC 10716. Leucine also stimulated the growth rate of the mutant. The stimulatory effect of leucine on bacitracin production is discussed in relation to control mechanisms and overproduction of antibiotics.