Process for the preparation of pseudomonic acid A antibiotic by microbiological method

The present invention relates to a microbiological method for the manufacture of the antibiotic pseudomonic acid A (mupirocin). A procedure for the preparation of pseudomonic acid A comprising submerged cultivation of a Pseudomonas bacterium strain capable of biosynthesis of the substantially pure pseudomonic acid A in aerated conditions via fermentation; and isolation of the desired compound is disclosed. In particular, the procedure of the present invention comprises cultivation of the Pseudomonas sp. bacterium strain No. 19/26 deposited under accession No. NCAIM(P)B 001235 in the National Collection of the Agricultural and Industrial Microorganisms, Budapest, Hungary, or its pseudomonic acid A-producing mutant or variant, on a medium at a temperature of between about 20° C. and 30° C. containing organic nitrogen and carbon sources and, optionally, mineral salts.