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.