A Preliminary Study of the Formation, Assay and Stability of Tyrothricin

SUMMARY: Strain selection and the addition of yeast extract to the medium have enabled high yields of tyrothricin to be produced from the culture fluids of Bacillus brevis. Contrary to the accepted view, this organism does ferment carbohydrates with the production of acid, and a description of the characters of the organism is given. A method of assaying tyrothricin has been developed and used to investigate the stability of aqueous solutions of the material. Tyrothricin produced in aerated submerged culture appears to be more stable in solution than that produced by surface culture.