Increases biofilm dispersal. Acts by binding directly to the signaling molecule cyclic-di-GMP, which decreases the intracellular concentration of cyclic-di-GMP and leads to biofilm dispersal. Also controls other biofilm-related phenotypes such as cell motility, cell size, cell aggregation and production of extracellular DNA and extracellular polysaccharides (EPS). Does not act as a phosphodiesterase. Expression is time dependent in biofilms and is controlled by BdcR. Mutant shows decreased biofilm dispersal. Deletion increases the cyclic-di GMP concentration in the cell. Belongs to the short-chain dehydrogenases/reductases (SDR) family.