Production of erythromycin using a carrier-supported mycelium in an air-lift bioreactor

Abstract

$\underline{Streptomyces}$ $\underline{erythreus}$ grew resulting highly viscous culture broth with a rich medium in flask culture, but limiting the phosphate concentration made the mixing of broth easy with decreased cell growth and increased the specific erythromycin production rate from 557 $\mu$g/g-cell$\cdot$hr to 1200 $\mu$g/g-cell$\cdot$hr. When the phosphate concentration was limited by corn steep liquor which contained phosphate at 5\%, the specific production rate was further increased to 2898 $\mu g/g-cell \cdot hr$. To improve the productivity of erythromycin, immobilization of $\underline{Streptomyces}$ $\underline{erythreus}$ was conducted by the cultivation of spore-entrapped celite particles in rich medium and the immobilized cells were used for the production of erythromycin in an air-lift bioreactor by a repeated-fed batch mode. In rich medium, the operation of bioreactor became impossible by the extensive growth of mycelia detatched from the immobilized particles. In phosphatelimited medium where corn steep liquor concentration was reduced from 30 g/l to 1 g/l, the problems in operation were solved and erythromycin productivity was increased to 3,2 fold high comparing with batch mode or bioreactor operation with rich medium, respectively.