TAG: GS 3: ECOLOGY AND ENVIRONMENT
THE CONTEXT: A groundbreaking study led by Gokce Ustunisik and her team at the South Dakota School of Mines and Technology reveals the potential of certain bacteria to accelerate the mineralization of carbon dioxide (CO2) under extreme conditions.
EXPLANATION:
- The application of these microbes could revolutionize the storage of CO2 in deep underground sites, offering a more rapid and durable solution to mitigating greenhouse gas emissions.
Isolation of Geobacillus Bacteria:
- The researchers isolated Geobacillus bacteria species from a compost pile in Washington state known for their resilience to high temperatures and pressures.
- Geobacillus bacteria were chosen for their ability to thrive under extreme conditions, making them suitable candidates for underground CO2 storage.
Laboratory Tests and Findings:
- Laboratory tests compared the rate of CO2 mineralization with and without the presence of these microbes under conditions resembling those found deep underground.
- The absence of microbes resulted in negligible CO2 mineralization, a process that typically takes years under natural geological conditions.
- With the Geobacillus bacteria, mineral crystals formed within a remarkable 10 days at 80°C (176°F) and pressures 500 times that of sea level.
Role of Carbonic Anhydrase Enzyme:
- The key to the rapid mineralization rate is attributed to an enzyme produced by the bacteria, known as carbonic anhydrase.
- This enzyme efficiently reduces the acidity of the CO2 solution, facilitating the formation of carbonate minerals from released magnesium and calcium in the rock.
Potential Storage Sites:
- The accelerated mineralization process opens up possibilities for using depleted oil and gas reservoirs as deep underground storage sites for CO2.
- The speed at which CO2 can be converted into mineral crystals under extreme conditions enhances the feasibility and efficiency of long-term storage.
Challenges and Future Steps:
- The researchers have not disclosed the exact species of bacteria due to pending patent issues.
- Further testing will involve Bacillus bacteria from a former mine shaft in South Dakota and genetically modified strains to identify the most effective microbes.
- The next phase includes evaluating the performance of these microbes in an actual storage well.
Concerns and Criticisms:
- Outside researchers emphasize the need for addressing concerns about the resilience, food source, turnover rates, and adaptability of these organisms to various alkaline environments.
- The introduction of nutrients along with the microbes to sustain them raises practical challenges.
- The potential spread of introduced or genetically modified microbes in subsurface environments poses ecological and regulatory concerns.
Conclusion:
- The study signifies a significant step towards developing a novel approach to carbon sequestration by leveraging bacteria to expedite CO2 mineralization under extreme conditions. While challenges and uncertainties persist, the promise of accelerating the process to a mere 10 days could have substantial implications for mitigating climate change by securely storing CO2 in underground reservoirs.