Immobilization of carbonic anhydrase for enhancement of CO2 reactive absorption

CO2 reactiveabsorptioninaqueoussolventswasproposedinthe last decades as an affective process for post-combustion CO2 capture. The use of the enzyme carbonic anhydrase (CA) as promoter ofthereactiveabsorptionprocesswasstudiedandseveraloptions showed promising results in terms of CO2 capture rate enhancement thanks to the effect of CA catalysis of the CO2 hydration reaction to bicarbonate ions. The possibility to exploit this process at industrial scale for CO2 capture from flue gases, directly from air, and from any other gaseous mixture (e.g. biogas) depends on the possibility to reuse and recycle the enzyme. CA immobilization is one of the most effective solutions to this issue. The aim of this work is to develop two different techniques of covalent immobilization of CA that may satisfy the requirements for effectiveenhancementofthegas-liquidabsorptionprocess.Tothisaim, athermostableCAwasimmobilizedincross-linkedenzymeaggregates (CLEA) and through covalent attachment on fine particles. In both cases, paramagnetic nano-particles (PNP) were used so that magneticfieldassistedoperationscanbeproposedfortheenduse of the developed biocatalyst particles in the CO2 capture reactor. CommercialPNPwereincludedduringthepreparationofCLEAand adhocsynthetizedPNPwereusedassupportsfordirectbindingof CAthroughcarbodiimideactivation.PerformancesofbothbiocatalystswereassessedintermsofCO2 absorptionrateinastirredcell labscalereactorusingK2CO3 solutionaspotentialrealsolventsfor CO2 capture process.