Mac hypothesis in a superstring inspired model

We study a superstring inspired E₆ model based on the MAC hypothesis. We find two kinds of model in which the proton decay through the colored Higgs is naturally suppressed and every field in 27 of E₆ carries a role; a pair of colored fields in 27 are necessary to cause the MAC condensation and two doublet fields in 27 cause the usual Higgs mechanism at the electroweak breaking. The fields left in 27 are identified with quarks and leptons adding to v_L^c.