A process for desorbing CO2 gas from an ion-rich aqueous mixture comprising bicarbonate and hydrogen ions, includes providing micro-particles in the ion-rich aqueous mixture; and feeding the ion-rich aqueous mixture into a desorption reactor; the micro-particles comprising a support material and biocatalysts supported and stabilized by the support material and being sized and provided in a concentration in the desorption reactor such that the micro-particles are carried with the ion-rich aqueous mixture to promote transformation of the bicarbonate and hydrogen ions into CO2 gas and water, thereby producing a CO2 gas stream and an ion-depleted solution.