Immobilization of carbonic anhydrase for biomimetic CO2 capture

Novel post-combustion treatments include carbon capture and sequestration processes based on biomimetic strategies. These strategies include CO2 absorption into aqueous solution assisted by enzyme catalysis. Carbonic anhydrase catalyses CO2 hydration and it has been proposed as industrial biocatalyst for Carbon Capture and Storage (CCS) post-combustion processes. The recombinant enzyme SspCA, isolated from the thermophile bacterium Sulfurhydrogenibium sp. was characterized as potential biocatalyst for CO2 capture processes based on regenerative absorption into alkaline solutions. This paper reports results of a preliminary study focused on the immobilization of carbonic anhydrase on granular solids to improve biocatalyst stability at the typical operating conditions of the CO2 absorption processes. This study included the selection of solid supports and of the immobilization technique. Granular fine silica particles were adopted as enzyme carriers. Two classes of solids were investigated: 120 and 9 micronm d50 diameter. Bovine carbonic anhydrase was used as enzyme model in order to optimize immobilization procedure and activity assay for immobilized carbonic anhydrase. Enzyme-carrier covalent bonding was adopted as immobilization technique. In particular, solids were silanized and activated with respect to the enzyme by means of glutaraldehyde branches. For 120 micronm particles, the maximum enzyme loading resulted 40.3 mg of bovine CA per g of solids and the maximum yield resulted about 66.5% for initial CA concentration between 1.4 and 4 mg/mL. Copyright �� 2013, AIDIC Servizi S.r.l.