From the picture, I would say that is a pretty nice dresser and is probably built from plywood. If it is, it will easily hold the weight of a 55gal tank. The only concern I might have would be with the pressure points created by the "feet" of the dresser. So long as the feet distribute the weight over several inches, this also should be no problem. If you go this route, I'd buy a clear polyurethane and add three or four coats to the top of the dresser, this will help prevent water damage.