Growth of Streptomyces hygroscopicus in rotating-wall bioreactor under simulated microgravity inhibits rapamycin production

Growth of Streptomyces hygroscopicus under conditions of simulated microgra vity in a rotating-wall bioreactor resulted in a pellet form of growth, low ered dry cell weight, and inhibition of rapamycin production. With the addi tion of Teflon beads to the bioreactor; growth became much less pelleted, d ry cell weight increased but rapamycin production was still markedly inhibi ted. Growth under simulated microgravity favored extracellular production o f rapamycin, in contrast to a greater percentage of cell-bound rapamycin ob served under normal gravity conditions.