EFFECT OF NITROGEN CARBON RATIO ON THE SPECIFIC PRODUCTION-RATE OF SPIRAMYCIN BY STREPTOMYCES-AMBOFACIENS

Streptomyces ambofaciens was grown on a synthetic medium with glycerol (10g litre(-1)) and ammonium (20 mM) as carbon and nitrogen sources, respectively. Batch fermentation produced a specific production rare o f spiramycin (q(sp)) of 0.3 mg h(-1) g(-1) DCW. Improvement of spiramy cin production was achieved by fedbatch culture. The strong influence of the initial uptake rates of glycerol (q(gly)) and ammonium (q(NH4+) ) on the specific production rate of spiramycin (q(sp)) was demonstrat ed by conducting several fermentations with continuous feeding of glyc erol and ammonium, in different ratios. The specific production rate o f spiramycin was increased 10 fold. A low specific growth rate was als o necessary for spiramycin biosynthesis.