Accelerating Mineral Carbonation Using Carbonic Anhydrase

Abstract

Carbonic anhydrase (CA) enzymes have gained considerable attention for their potential use in carbon dioxide (CO2) capture technologies because they are able to catalyze rapidly the interconversion of aqueous CO2 and bicarbonate. However, there are challenges for widespread implementation including the need to develop mineralization process routes for permanent carbon storage. Mineral carbonation of highly reactive feedstocks may be limited by the supply rate of CO2. This rate limitation can be directly addressed by incorporating enzyme-catalyzed CO2 hydration. This study examined the effects of bovine carbonic anhydrase (BCA) and CO2-rich gas streams on the carbonation rate of brucite [Mg(OH)2], a highly reactive mineral. Alkaline brucite slurries were amended with BCA and supplied with 10% CO2 gas while aqueous chemistry and solids were monitored throughout the experiments (hours to days). In comparison to controls, brucite carbonation using BCA was accelerated by up to 240%. Nesquehonite [MgCO3·3H2O] precipitation limited the accumulation of hydrated CO2 species, apparently preventing BCA from catalyzing the dehydration reaction. Geochemical models reproduce observed reaction progress in all experiments, revealing a linear correlation between CO2 uptake and carbonation rate. Data demonstrates that carbonation in BCA-amended reactors remained limited by CO2 supply, implying further acceleration is possible.

Engineering the genetic components of a whole‐cell catalyst for improved enzymatic CO2 capture and utilization

“…Many entities in scientific and technological fields have made enormous efforts towards solving these difficulties. A biomimetic approach employing the enzyme carbonic anhydrase (CA) is considered to be a promising option for carbon capture, utilization, and storage (CCUS) (Power, Harrison, & Dipple, 2016;Savile & Lalonde, 2011;Srikanth, Alvarez-Gallego, Vanbroekhoven, & Pant, 2017). CA is a diffusion-limited enzyme that catalyzes the hydration of CO 2 , which is the rate-limiting step of HCO 3 − formation from CO 2 , with a k cat of up to 4.4 × 10 6 s −1 (Vullo et al, 2012).…”

A Review on Integrated Mineral Carbonation Process in Ultramafic Mine Deposit

“…Furthermore, seeding acid-generating materials with Acidithiobacillus spp. enhances magnesium ion leaching from silicate minerals (Power et al 2010); applying a cyanobacteria accelerates the precipitation of platy hydomagnesite (McCutcheon et al 2014); using carbonic anhydrase catalyzes the hydration of aqueous CO2 (Power et al 2016); pre-seeding carbonates promotes the carbonation nucleation (Zarandi et al 2016); pumping CO2 into tailing water increases CO2 gas content (Harrison 2014); and periodically adding small amounts of water keeps partial pore saturation at optimum levels (Assima et al 2013) which promotes the conversion of CO2 gas into a carbonate form. Moreover, the by-products of carbonation, such as photoautotroph biomass, can be harvested as biofuel (Power et al 2011).…”

Trends, application and future prospectives of microbial carbonic anhydrase mediated carbonation process for CCUS

“…On the other hand, with less reactive silicates, mineral dissolution limits the carbonation process (Power et al . ). Bond et al .…”

“…Thus, the inclusion of CA plays a vital role in the acceleration of carbonation. On the other hand, with less reactive silicates, mineral dissolution limits the carbonation process (Power et al 2016). Bond et al (2001) first successfully demonstrated the formation of calcium and magnesium carbonates through the use of bovine CA through mineral carbonation (Bond et al 2001;Power et al 2013b).…”