Antibiotics produced by Bacillus licheniformis 1. A Practical Chemically Defined Medium for Production

SUMMARY: The production of licheniformin-like antibacterial activity in culture by a single strain of Bacillus licheniformis required neutral or alkaline conditions, conveniently attained by the use of lactate rather than glucose as a source of carbon in a chemically defined medium. When the medium contained initially about 0.0P-0.10 yo nitrogen, supplied as asparagine or as ammonium lactate, and the cultures, harvested after 4-9 days a t 3 7 O, were sterilized by bringing to pH 2.5 and autoclaving, the inhibitory dilution against a test strain of Mycobacterium phlei was 1/160 or greater. Fluid from cultures in a chemically defined medium, containing 0.06 M ammonium lactate and 0.05 M sodium lactate, inhibited the test organism a t a dilution of 1/200-1200 (geometric mean, 530) in 44 consecutive batches of 100-200 1. culture fluid produced by incubation of cultures in shallow layers. The pH value of the harvested fluid was about 9 and the antibiotic material was partly bound by the cells. It was largely freed by adjustment to pH 2.5. When amino-acids were added to the medium either as a mixture of known amino