Summary NtrC‐mediated production of exopolysaccharides (EPS), essential components for Vibrio vulnificus biofilms, is highly increased in the presence of dicarboxylic or tricarboxylic acids. Gel‐shift assays showed that regulation of the EPS‐gene cluster I (EPS‐I cluster) by NtrC was direct via binding of phosphorylated NtrC (p‐NtrC) to the regulatory region of the EPS‐I cluster. In contrast, p‐NtrC did not bind to the EPS‐II...