In a groundbreaking study, researchers have demonstrated that engineered bacteria can accelerate the weathering of olivine, a silicate mineral, thereby enhancing its capacity for carbon dioxide (CO2) removal from the atmosphere. This process, known as mineral weathering, has long been recognized as a scalable strategy for CO2 capture and storage, but its slow natural rate has hindered industrial applications.
Accelerating Mineral Weathering
The study focuses on the role of siderophores, which are molecules secreted by bacteria to solubilize iron from minerals. The researchers investigated the marine bacterium Alteromonas macleodii, which naturally produces the siderophore petrobactin. They found that natural genetic regulation limits continuous siderophore production in mineral bioreactors, which is essential for enhancing olivine dissolution.
Engineering for Efficiency
To overcome this limitation, the team genetically engineered A. macleodii to enhance its siderophore production, achieving a remarkable 2.6-fold increase in the rate of olivine dissolution. This modification allows the bacteria to continuously produce siderophores, which are crucial for preventing the passivation of minerals by iron oxides during the weathering process.
Experimental Setup and Results
The researchers constructed pilot-scale continuous mineral bioreactors using unprocessed seawater and a renewable acetate feedstock to weather 4 kg of olivine. In these reactors, they measured a direct removal of 0.50 g CO2 per day from the air through the generation of alkalinity. This alkalinity is primarily composed of stable bicarbonate ions derived from atmospheric CO2, highlighting the potential of this method for long-term carbon storage.
Life-Cycle Analysis and Future Implications
A life-cycle analysis indicated that utilizing renewable feedstocks and minimizing the replenishment of modified cells are critical for achieving net CO2 removal at scale. The findings suggest that a tank-based unit operation, which accelerates the dissolution of silicate minerals in a low-cost environmental medium like seawater, could enable large-scale, measurable CO2 storage over decades.
This innovative approach to carbon capture and storage, leveraging engineered bacteria and mineral weathering, presents a promising avenue for addressing climate change challenges.
This article was produced by NeonPulse.today using human and AI-assisted editorial processes, based on publicly available information. Content may be edited for clarity and style.
