Involved in the acrylate pathway for the conversion of D-lactic acid to propionic acid. Catalyzes the reversible dehydration of Lactoyl-CoA and 2-hydroxybutyroyl-CoA to acryloyl-CoA and crotonyl-CoA, respectively. (R)-lactoyl-CoA = acryloyl-CoA + H2O (2R)-hydroxybutanoyl-CoA = (2E)-butenoyl-CoA + H2O Binds 1 [4Fe-4S] cluster. Activated by the LcdC protein. Heterodimer of an alpha (LcdA) and a beta (LcdB) subunit. The elimination of water from 2-hydroxybutyryl-CoA or lactoyl-CoA occurs in a syn mode. Belongs to the FldB/FldC dehydratase alpha/beta subunit family.