Abstract
The present paper deals with the investigation attempted to demonstrate a precursor of riboflavin in the culture of Lactobacillus plantarum using the inhibitors. Lactobacillus plantarum was grown in bouillon or wort and 3 types of riboflavin was determined in bacterial cell and broth in the presence of various antienzymic substances, and tried to discover a precursor of riboflavin formation by interfering with PAS or sulfamine. The total riboflavin content of growing bacillus was higher in bouillon culture than in wort. The amount of riboflavin in bacterial cell was higher than in the broth. Bacterial cell contained high FAD, less FMN and no free riboflavin. On the other hand, in the broth free riboflavin was the highest, FMN was slight and none of FAD. Fluorescent substances were found having Rf 0.14 in the cell and Rf 0.49 in the broth. KCN, NaF, PAS or CH_2ICOOH inhibited the riboflavin formation, while an increase was observed by sulfamine and malonate. Non-acetylatable diazotizable amine which was supposed to be a precursor of riboflavin synthesis was accumulated in the presence of PAS or sulfamine.
