Effect of sulphanilamide on citric acid production by Aspergillus niger

Abstract

It has been shown that the mechanism of resistance to sulphanilamide toxicity in E. coli involves the enhanced formation of coenzyme A which is required for the acetylation of the drug. A similar increase in the coenzyme A levels of the cells has been observed in S. cerevisiae subjected to sulphanilamide toxicity. An interesting observation made in the experiments with S. cerevisiae was that, concomitant with the increase in the coenzyme A levels of the cells, there was an enhancement in the levels of ergosterol as well. In view of the known role of coenzyme A in sterol biosynthesis, it was considered of interest to investigate the effect of sulphanilamide toxicity on other biosynthetic processes involving the action of coenzyme A. Accordingly the effect of the drug on citric acid production by a citric acid-accumulating strain of Aspergillus niger was investigated. The results presented here show that the production of citric acid by the mould is markedly inhibited by sulphanilamide.