Catalyzes the cleavage of the C5-C6 bond of 2-hydroxy-6-oxononadienedioate and 2-hydroxy-6-oxononatrienedioate, a dienol ring fission product of the bacterial meta-cleavage pathway for degradation of phenylpropionic acid. (2Z,4E)-2-hydroxy-6-oxonona-2,4-dienedioate + H2O = (2Z)-2-hydroxypenta-2,4-dienoate + H(+) + succinate (2Z,4E,7E)-2-hydroxy-6-oxonona-2,4,7-trienedioate + H2O = (2Z)-2-hydroxypenta-2,4-dienoate + fumarate + H(+) Aromatic compound metabolism; 3-phenylpropanoate degradation. Homodimer. Belongs to the AB hydrolase superfamily. MhpC family. Extended N-terminus. Extended N-terminus.