We construct an 11D supermembrane with topological central charges induced through an irreducible winding on a G2 manifold realized from the T 7 /Z 3 2 orbifold construction. The Hamiltonian H of the theory on a T 7 target has a discrete spectrum. Within the discrete symmetries of H associated with large diffeomorphisms, the Z 2 ×Z 2 ×Z 2 group of automorphisms of the quaternionic subspaces preserving the octonionic structure is relevant. By performing the corresponding identification on the target space, the supermembrane may be formulated on a G2 manifold, preserving the discreteness of its supersymmetric spectrum. The corresponding 4D low energy effective field theory has N = 1 supersymmetry.