Catalyzes the NAD(+)-dependent oxidative decarboxylation of D-malate into pyruvate. Is essential for aerobic growth on D-malate as the sole carbon source. But is not required for anaerobic D-malate utilization, although DmlA is expressed and active in those conditions. Appears to be not able to use L-tartrate as a substrate for dehydrogenation instead of D-malate. (R)-malate + NAD(+) = CO2 + NADH + pyruvate Binds 1 Mg(2+) or Mn(2+) ion per subunit. By the transcriptional regulator DmlR in the presence of D-malate or L- or meso-tartrate, under aerobic conditions. Is not induced by L-malate, D-tartrate or succinate. Is also induced at high levels under anaerobic conditions in the presence of D-malate and its expression is more than 5-fold greater than the one under aerobic conditions. Repressed by glucose or nitrate under anaerobic conditions. During aerobic growth, appears to be repressed by the DcuS-DcuR two-component system, and is not repressed by glucose. Deletion of dmlA inhibits aerobic growth on D-malate but does not impair slow anaerobic growth on D-malate. Aerobic growth on D-malate requires, in addition to DmlA, the presence of the aerobic C4-dicarboxylate transporter DctA, for D-malate uptake. Meso-tartrate or L-tartrate are not able to support aerobic growth. Slow anaerobic growth on D-malate is observed only when glycerol is also provided as an electron donor, and D-malate is used in fumarate respiration, so is not dependent on DmlA. Belongs to the isocitrate and isopropylmalate dehydrogenases family.