The authority is hereby declared to be performing a public function in behalf of the municipality with respect to which it is organized and to be a public instrumentality of such municipality. Accordingly, the authority and all properties at any time owned by it and the income from the properties and all bonds issued by the authority and the income from the bonds, shall be exempt from all taxation in the state. Also, for purposes of the Tennessee Securities Act of 1980, compiled in title 48, chapter 1, part 1, bonds issued by the authority shall be deemed to be securities issued by a public instrumentality or a political subdivision of the state.