Physiological characteristics of immobilized Streptomyces cells in continuous cultures at different dilution rates

Abstract

Physiological characteristics such as specific productivity, morphology of Streptomyces cells immobilized on celite beads, and operational stability at different dilution rates were investigated in continuous immobilized-cell cultures for the production of kasugamycin. At a dilution rate (D) of 0.05 h(-1), a relatively high specific productivity was attained and the loss of cell-loaded beads was negligible. At D=0.1 h(-1), a higher specific productivity and cell concentration could be obtained, resulting in a significantly improved volumetric kasugamycin productivity. However, no stable operation could be maintained due to a significant loss of cell-loaded beads from the reactor that was caused by their fluffy morphology developed in the later stage. At D=0.2 h(-1), the production of kasugamycin and cell growth were observed to be severely inhibited by the high concentration of residual maltose.