Mineral CO2 sequestration by environmental biotechnological processes

CO2 sequestration may be an avenue to mitigate climate change. CO2 sequestration by mineral carbonation can be achieved by the reaction of CO2 with alkaline silicates. Here, we evaluate how alkaline silicate mineral-based CO2 sequestration can be achieved using environmental biotechnological processes. Several biotechnological processes rely on the sequence of (i) an acid-producing reaction such as nitrification and anaerobic fermentation and (ii) an alkalinity-producing reaction such as denitrification and methanogenesis. Whereas the acid-producing reaction can be used to enhance the dissolution of, for example, alkaline calcium silicates, the subsequent alkalinity-producing step can precipitate CaCO3. We quantitatively evaluate the potential of these processes for CO2 sequestration and propose that optimization of these processes could contribute to climate change mitigation strategies.