Catalyzes a 2-step reaction, involving the ATP-dependent carboxylation of the covalently attached biotin in the first step and the transfer of the carboxyl group to pyruvate in the second, leading to oxaloacetate production. Fulfills an anaplerotic function in B.subtilis as it is necessary for growth on glucose, but is not required for sporulation. ATP + hydrogencarbonate + pyruvate = ADP + H(+) + oxaloacetate + phosphate Allosterically activated by acetyl-CoA. Inhibited by the biotin-complexing protein avidin. Homotetramer. Constitutively expressed.