RESUMO
The possibility of shortening the thermal sterilization time for cultivating media was demonstrated in chlortetracycline fermentation with an industrial strain of Streptomyces aureofaciens. The medium was artificially contaminated with a mixture of eight strains of G+ and G- bacteria isolated from contaminated industrial fermentors, and the following chemical agents, either alone or in combination, were added: formaldehyde, phenol. dimethylformamide, p-aminosalicylic acid and nitrofurazone. Dimethylformamide was inhibitory even at 0.08%. formaldehyde concentrations higher than 0.05%, Nitrofurazone stimulated chlortetracycline production. The best combination was 0.01% formaldehyde added before, and 2.10-3% nitrofurazone added after short sterilization at 120 degrees C.