(a) The commissioner shall establish such units within the department as he or she deems proper for its administration and shall designate persons to be directors and assistant directors of such units to exercise such authority as he or she may delegate to them in writing.

(b) The commissioner shall have the authority to employ as many persons as he or she deems necessary for the administration of the department and for the discharge of the duties of his or her office. He or she shall issue all necessary directions, instructions, orders, and rules applicable to such persons. He or she shall have authority, as he or she deems proper, to employ, assign, compensate, and discharge employees of the department within the limitations of the department's appropriation and the restrictions set forth by law.

(c) All employees of the department shall be compensated upon a fixed salary basis and no person shall be compensated for services to the department on a commission or contingent fee basis.

(d) Neither the commissioner nor any officer or employee of the department shall be given or receive any fee, compensation, loan, gift, or other thing of value in addition to the compensation and expense allowance provided by law for any service or pretended service either rendered or to be rendered as commissioner or as an officer or employee of the department.

(e) The commissioner shall delegate to such officers and employees of the department as he or she may designate the law enforcement powers and duties of the department as set out in Code Section 40-16-2. All officers and employees to whom such law enforcement powers and duties are delegated must be certified by the Georgia Peace Officer Standards and Training Council as having successfully completed the course of training required by Chapter 8 of Title 35, the "Georgia Peace Officer Standards and Training Act."