Catalyzes hydrolysis of the D-alanyl-D-alanine dipeptide. May have a role in cell-wall turnover. D-alanyl-D-alanine + H2O = 2 D-alanine Binds 1 zinc ion per subunit. kcat is 170 sec(-1) with D-Ala-D-Ala. kcat is 70 sec(-1) with L-Ala-D-Ala. Belongs to the peptidase M15D family.