Yoshihiko Oka

Product inhibition and its removal on josamycin fermentation by Streptomyces narbonensis var. josamyceticus

Abstract Josamycin formation was shown to be closely associated with the degree of mycelial growth. Media using glycerol or glucose were slight in josamycin accumulation. However, the mycelial growth and product formation were interrupted in the course of the fermentation. The self-resistance level of the producing organism against josamycin was shown to be not higher than 1 mg per ml. In media using fatty oil, the organism grew smoothly and gave a concentration of josamycin at least 5 times higher than the self-resistance level Most of the josamycin was distributed in the oily phase of the broth. The josamycin concentration of the water phase of the broth was less than the self-resistance level, except in the later period of the fermentation. Unsaturated fatty acids remaining in the broth were found to be the best extractors of josamycin. It was concluded that the enhanced josamycin accumulation of this fermentation resulted from the removal of the product inhibition.

Effect of Mineral Salts on Apparent Viscosity and a Ratio of Product Components in Josamycin Fermentation

Abstract 3- O -Deacetyl-josamycin (DeAcJM) was accumulated as a by-product in josamycin fermentation by Streptomyces narbonensis var. josamyceticus . Josamycin accumulation was apparently related to the degree of mycelial growth and the accelerative increase in apparent viscosity of the broth. However, the oxygen transfer coefficient was reduced by an increase in the apparent visensity and had a significant influence on josamycin formation. Josamycin accumulation was found to be inversely proportional to the DeAcJM-ratio, defined as the ratio of DeAcJM to the sum of josamycin and DeAcJM. Several ingredients of the medium and fermentation conditions were observed to alter the DeAcJM-ratio. In particular, the addition of mineral salts acted dramatically to reduce the apparent viscosity and DeAcJM-ratio. The reduction of the apparent viscosity causes improvement in the oxygen transfer coefficient. This brings about a considerable decrease in the DeAcJM-ratio along with a convergence in josamycin while increasing josamycin accumulation.