Phosphodiesterase (PDE) that catalyzes the hydrolysis of cyclic diguanylate (c-di-GMP). Positively regulates motility and negatively regulates biofilm formation. cyclic di-3',5'-guanylate + H2O = 5'-phosphoguanylyl(3'->5')guanosine + H(+) Deletion mutant exhibits decreased motility. Mutation causes a slight decrease in flaA expression but does not affect flagellar morphology. Mutant has enhanced biofilm formation and vps gene expression.