Catalyzes the Fe(2+) and alpha-ketoglutarate-dependent conversion of (3S,5S)-carbapenam to (5R)-carbapenem, an essential step in carbapenem antibiotic biosynthesis. (3S,5S)-carbapenam-3-caboxylate + 2-oxoglutarate + O2 = (5R)-carbapenem-3-carboxylate + CO2 + H2O + succinate Binds 1 Fe(2+) per subunit. Inhibited by L-N-acetylproline and by D-N-acetylproline. Homohexamer. Dimer of trimers. Belongs to the TfdA dioxygenase family.