GRAMICIDIN-S PRODUCTION BY BACILLUS-BREVIS IN SIMULATED MICROGRAVITY

In a continuing study of microbial secondary metabolism in simulated m icrogravity, we have examined gramicidin S (GS) production by Bacillus brevis strain Nagano in NASA High Aspect Rotating Vessels (HARVs), wh ich are designed to simulate some aspects of microgravity, Growth and GS production were found to occur under simulated microgravity. When p erformance under simulated microgravity was compared with that under n ormal gravity conditions in the bioreactors, GS production was found t o be unaffected by simulated microgravity. The repressive effect of gl ycerol in flask fermentations was not observed in the HARV. Thus the n egative effect of glycerol on specific GS formation is dependent on sh ear and/or vessel geometry, not gravity.