Abstract
Investigating the inhibitory action of Na-arsenate upon riboflavin formation by acetone-butanol fermentation bacteria, it was found that Na-arsenate inhibited the fermentation along with riboflavin formation when it was used in high concentration. But in its low concentration, riboflavin formation was depressed markedly. And it was concluded that the inhibitory action of arsenate upon riboflavin formation would be attributed to the inhibition on the action of the riboflavin-synthesizing enzyme system as in the case of iron.
