BOSTON – Scientists have engineered marine bacteria to significantly speed up the natural process of rock weathering, offering a new method to remove carbon dioxide from the atmosphere. A collaborative research team, primarily from Harvard and Stanford, genetically modified a common marine bacterium to boost its ability to break down rocks, increasing the rate of carbon removal by 2.6 times in laboratory settings. This development could help enhance carbon capture efforts globally.
Boosting Nature's Carbon Trap
Rock weathering is a natural process that draws carbon dioxide (CO2) from the atmosphere over hundreds of thousands of years. Rainwater reacts with CO2 to form carbonic acid, which then dissolves rocks and minerals. The dissolved minerals eventually reach the ocean, where they trap CO2 as bicarbonate, helping to cool the planet. Scientists have long explored ways to accelerate this slow natural cycle, known as enhanced rock weathering (ERW), often by crushing rocks into fine dust and spreading them on land or in water. However, this method alone is often too slow and costly for industrial-scale impact.[phys+3]
The breakthrough involves genetically engineering Alteromonas macleodii, a widespread marine bacterium. This bacterium was modified to produce much higher amounts of molecules called siderophores. Siderophores play a crucial role by extracting iron from silicate minerals. This process effectively "de-rusts" the mineral surface, which typically slows down natural weathering. By continuously producing these molecules, the engineered bacteria maintain faster dissolution of the rocks. Natural bacteria usually stop making siderophores once they have enough iron for their growth, limiting their weathering power.[phys+6]
In customized bioreactors with a continuous flow of seawater, the engineered bacteria increased the weathering rate of the silicate mineral olivine by 2.6 times. This boost directly increased the amount of CO2 removed from the air. Neil Dalvie, Ph.D., a chemical engineer and the study's first author, spearheaded this project. The findings were published on August 28, 2026, in the journal Nature Biotechnology. Pamela Silver, Ph.D., a founding core faculty member at the Wyss Institute, and Michael Springer, Ph.D., an associate faculty member, led the research team.[wyss+5]
Another Microbial Approach for Carbon and Metals
Separately, researchers at Cornell University have also developed engineered bacteria to accelerate rock weathering. Their work, published on August 5, 2026, in Scientific Reports, focuses on a bacterium called Gluconobacter oxydans (G. oxydans). This engineered strain rapidly breaks down ultramafic minerals, which are rich in magnesium and iron.[news]
The Cornell team found that G. oxydans not only speeds up weathering but also offers additional benefits. The process releases valuable metals like cobalt and nickel, which are essential for manufacturing electric vehicle batteries. Furthermore, the dissolved magnesium is converted into magnesium oxalate, a mineral capable of storing twice as much carbon per magnesium atom as the more commonly studied mineral magnesite. Esteban Gazel, a professor at Cornell's Department of Earth and Atmospheric Sciences, said this work shows how biology can dramatically accelerate natural carbon removal. He noted it also creates value through critical mineral recovery. Experiments showed that direct contact between G. oxydans and mineral surfaces significantly increased dissolution rates. The engineered bacteria extracted up to 75% of the magnesium from olivine samples in just 15 days. Buz Barstow, an associate professor at Cornell, led the engineering of this bacterial strain.[news+6]
The Promise of Enhanced Rock Weathering
Natural rock weathering is a fundamental part of Earth's carbon cycle. It helps regulate atmospheric CO2 levels and climate by forming new carbon-bearing minerals. However, this process takes place over geological timescales, too slowly to address current human-caused climate change. Enhanced rock weathering aims to accelerate this by using finely ground silicate rocks, like basalt or olivine. These crushed rocks are spread on agricultural fields or introduced into water to increase their surface area and reactivity.[phys+8]
Microorganisms naturally play a role in this process by secreting acids and enzymes that break down rocks. The new engineered bacterial approaches significantly amplify this microbial contribution. This could make ERW a more viable option for large-scale carbon removal. Some estimates suggest that ERW could remove hundreds of millions to billions of tons of carbon annually by 2050.[phys+7]
Next Steps and Remaining Challenges
While promising, scaling up these engineered bacterial systems faces several challenges. Current ERW strategies, even with crushed rocks, are still too slow and costly to make a global impact without further advancements. The cost of enhanced rock weathering can vary widely, from $16 to $343 per tonne of CO2 removed, depending on factors like location and mineral source. Some estimates for microbial enhanced weathering suggest costs as low as $21 per ton.[phys+2]
Researchers need to identify lower-cost materials to grow the bacteria and understand the long-term stability of the carbon-storing minerals produced. There are also concerns about potential environmental impacts, such as heavy metals in pulverized rock accumulating in soil. Robust monitoring, reporting, and verification (MRV) methods are crucial to accurately measure how much carbon is permanently stored.[latitudemedia+3]
Despite these hurdles, experts agree that carbon removal technologies are necessary to meet climate change targets. Engineered bacteria represent a significant step toward making enhanced rock weathering a more effective and scalable solution for climate mitigation. The ongoing research aims to refine these biological tools to help capture and store atmospheric CO2 more efficiently for generations to come.[counteract+2]
