The commissioner, for services rendered in connection with the liquidation of state trust companies hereunder, shall be entitled to actual expenses incurred in connection with the liquidation of each state trust company, including therein a reasonable sum for the time of the examiners and other agents of the commissioner, which expenses shall be a prior lien on the assets of such state trust company so liquidated until paid in full; and the commissioner shall have authority to prescribe reasonable rules and regulations for fixing such expenses.