Part of a complex that catalyzes the reversible cleavage of acetyl-CoA, allowing growth on acetate as sole source of carbon and energy. The alpha-epsilon subcomponent functions as a carbon monoxide dehydrogenase. The precise role of the epsilon subunit is unclear; it may have a stabilizing role within the alpha(2)epsilon(2) component and/or be involved in electron transfer to FAD during a potential FAD-mediated CO oxidation. One-carbon metabolism; methanogenesis from acetate. Heterotetramer of two alpha and two epsilon subunits. The ACDS complex is made up of alpha, epsilon, beta, gamma and delta subunits with a probable stoichiometry of (alpha(2)epsilon(2))(4)-beta(8)-(gamma(1)delta(1))(8). Belongs to the CdhB family.