Plays an essential role in chain termination during de novo fatty acid synthesis (Probable). Possesses thioesterase activity for medium chain acyl-ACPs. Substrate preference is 14:0 > 16:0 > 16:1 (PubMed:21831316, PubMed:29491418, PubMed:30409825). H2O + tetradecanoyl-[ACP] = H(+) + holo-[ACP] + tetradecanoate H2O + hexadecanoyl-[ACP] = H(+) + hexadecanoate + holo-[ACP] Belongs to the acyl-ACP thioesterase family.