Research on Enhanced CO2 Sequestration in Deep Saline Aquifers by Integrated Biological and Biomimetic Strategies

Deep saline aquifers hold great potential for CO2 sequestration, yet research on their bio-carbon fixation capacity remains scarce. This study collected formation water from a saline aquifer in southern China and pursued two objectives. First, using the Type II RubisCO gene (cbbM) as a biomarker, a highly sensitive qPCR system revealed gene copy numbers ranging from 2.6×10⁷ to 1.0×10⁸ copies/mL—the first reported measurement of its kind. Second, under simulated reservoir conditions (20 MPa, 80 °C) that replicate supercritical CO2 and mineral kinetics, we compared natural carbonic anhydrase with a biomimetic material (10% Co@ZIF-8/Ag) for mineral carbonation. The blank control fixed 3.37 mg CO2 per mL of formation water. Natural carbonic anhydrase achieved 3.45 mg CO2/mL, while the biomimetic enzyme reached 3.63 mg CO2/mL-a 7.7% increase over the control. This study establishes a bio–biomimetic integrated framework for evaluating synergistic CO2 sequestration in deep saline aquifers, elucidating cooperative enhancement mechanisms under extreme conditions. It provides empirical suppot for advancing geological carbon storage toward a "bio-geological synergy" paradigm, and the proposed methodology can be extended to assess sequestration potential in diverse geological storage systems worldwide.