INFLUENCE OF AERATION AND CARBON SOURCE ON PRODUCTION OF MICROCIN B17BY ESCHERICHIA-COLI ZK650

Previous studies [Connell et al. (1987) Mol Microbiol 1. 195-201] have shown that expression of the microcin B17 (MccB17) promoter is invers ely related to the growth rate of the culture, when slower growth was brought about by limitation of sources of carbon, nitrogen or phosphor us. When eve used oxygen limitation to decrease growth in a glucose-ba sed chemically defined medium, we found specific MccB17 production to be positively related to growth rate and extent. On the other hand, wh en we examined various nutritional variations of media, specific produ ction of MccB17 showed a negative relationship to growth rate and exte nt, as would be predicted by the findings of Connell et al. (1987). Gl ucose, glycerol and acetate were found to repress MccB17 production, s uccinate was not repressive. Succinate is an excellent carbon source f or production of MccB17 since high levels can be used with no or littl e interference in product synthesis.