Section 56. The commonwealth, acting by and through the department, may contract with the cities and towns of the commonwealth, acting by and through urban renewal agencies to provide financial assistance for residential, commercial including the conduct of a trade or business by governmental or nonprofit entities or industrial urban renewal projects as authorized by the provisions of this chapter. Such state financial assistance may be provided only for projects which are to be redeveloped for residential, commercial or industrial reuse, and which projects are ineligible for federal capital grants under federal legislation or for which a grant application has been denied. In determining whether a project is rendered ineligible for federal capital-grant assistance, the provisions of federal legislation permitting a limited amount of redevelopment for nonresidential uses need not be considered unless federal funds have been made available under such provisions.