Such bonds, as are provided for in Section 59-9-37, shall be general obligations of the county, and for the payment of such bonds and the interest thereon, the full faith, credit and resources of such county shall be and are hereby irrevocably pledged, and it shall be the mandatory duty of the board of supervisors of such county annually to levy upon all taxable property within such county an ad valorem tax sufficient to provide for the payment of such bonds as they mature and the interest thereon as it accrues, and the proceeds of such tax levy shall be used for no other purpose. In its discretion, such board of supervisors may also pledge for the payment of such bonds and interest thereon the revenues from facilities operated by the county port authority or county development commission, and any surplus revenues accruing to such county under and by virtue of Sections 65-33-45 and 65-33-47, Mississippi Code of 1972, and not theretofore pledged or hypothecated, and any other surplus funds available to such county from any other source, and not theretofore pledged or hypothecated. The board of supervisors of such county is further authorized, in its discretion, to issue revenue bonds of such county to provide funds for any purpose or purposes set out in this chapter, in the same manner as provided in Section 59-9-57 for the issuance of joint county and municipal revenue bonds, except that the board of supervisors of such county shall be authorized to issue such revenue bonds without the necessity of joint or concurrent action by any municipality, or the necessity of a separate election in such municipality, and such revenue bonds may be secured, in the discretion of the board of supervisors of such county, as provided in the preceding sentence hereof.