As each authority will be performing essential governmental functions in the exercise of the powers conferred upon it by this chapter, the state covenants with the holders of the bonds of an authority that the authority shall be required to pay no taxes or assessments upon any of the property acquired by it or under its jurisdiction, control, possession, or supervision or upon its activities in the operation or maintenance of any facilities maintained or acquired by it or any fees, rentals, or other charges for the use of such facilities or other income received by the authority and that the bonds and notes of the authority, their transfer, and the income therefrom shall at all times be exempt from taxation within the state. The exemption from taxation provided in this Code section shall not extend to tenants or lessees of the authority and shall not include exemptions from sales and use taxes on property purchased by the authority or for use by the authority. No authority shall be required to pay any intangible tax on the recording of any mortgage held or granted by the authority.