Engineered bacteria speed up CO2 removal

August 28, 2026

Scientists have genetically modified a common ocean bacterium to accelerate the natural weathering of rocks, potentially opening a new pathway for removing carbon dioxide from the atmosphere.

Researchers from Harvard University’s Wyss Institute, Harvard Medical School, and the Stanford Doerr School of Sustainability engineered the marine bacterium Alteromonas macleodii to enhance the breakdown of olivine, a silicate mineral capable of supporting long-term carbon sequestration.

In laboratory and pilot-scale experiments, the modified microbes increased olivine weathering by 2.6 times compared with control conditions, while also boosting the system’s ability to capture atmospheric CO2.

How rock weathering naturally removes CO2

Rock weathering is an important part of Earth’s natural carbon cycle. When silicate minerals such as olivine interact with water, air, and living organisms, they gradually dissolve and release elements including magnesium, iron, and silicon.

During this chemical process, carbon dioxide dissolved in water is converted into bicarbonate. This allows carbon to remain stored in a stable dissolved form, potentially keeping it out of the atmosphere for long periods.

Natural weathering, however, is extremely slow. One major obstacle occurs when iron released from minerals reacts with oxygen and forms an oxidized layer on the rock surface.

Similar to rust forming on metal, this coating creates a barrier that slows further mineral dissolution and reduces the rate at which weathering can consume CO2.

Engineered bacteria help remove iron coatings

The scientists focused on siderophores — specialized molecules produced by certain microorganisms that bind strongly to oxidized iron.

By capturing the iron and helping dissolve it into surrounding water, siderophores can remove the mineral’s protective iron coating. This exposes fresh olivine surfaces to seawater, allowing chemical weathering to continue more rapidly.

Under natural conditions, however, bacteria regulate siderophore production according to their nutritional needs. Once the microbes acquire sufficient iron, production declines, reducing their ability to continuously clear oxidized iron from the mineral.

To overcome this limitation, researchers genetically modified A. macleodii so that siderophore production remained active even when sufficient iron was available.

The modification effectively separated siderophore production from environmental iron concentrations, enabling the microorganisms to continuously support olivine dissolution.

Pilot-scale system demonstrates atmospheric carbon capture

Following encouraging early laboratory tests, the research team constructed larger bioreactors to examine whether the approach could operate under conditions closer to a real-world system.

The reactors contained several kilograms of green olivine sand submerged in untreated seawater collected from Boston Harbor.

Seawater containing the engineered bacteria was continuously circulated across the mineral. This setup allowed scientists to monitor dissolution and carbon removal under stable operating conditions rather than relying solely on small laboratory experiments.

Eventually, the experimental system captured approximately 0.5 grams of atmospheric CO2 each day.

Most importantly, olivine exposed to the engineered microorganisms weathered around 2.6 times faster than under the researchers’ control conditions.

The results provide evidence that synthetic biology could potentially accelerate geological carbon-removal processes that would otherwise take place over much longer timescales.

Synthetic biology could enhance natural climate processes

Rather than creating an entirely new carbon-removal mechanism, the approach is designed to strengthen a process that already plays a role in regulating Earth's climate.

Enhanced rock weathering has attracted increasing attention as a potential carbon dioxide removal technology because silicate minerals are abundant and the resulting bicarbonate can provide durable carbon storage.

Using microorganisms to accelerate the process could potentially improve its effectiveness while reducing some of the limitations associated with conventional enhanced weathering strategies.

The researchers say the work demonstrates how biologically inspired engineering and synthetic biology could be combined with naturally occurring geological processes to develop new climate solutions.

Researchers examine the carbon footprint of scaling up

The scientists also conducted a life-cycle assessment to evaluate emissions and carbon capture across the biological, geological, and chemical stages of the proposed system.

This analysis is particularly important because a carbon-removal technology must ultimately capture more greenhouse gases than are emitted through mining, transportation, infrastructure, energy consumption, and other operational activities.

The assessment helped researchers identify the factors that would have the greatest influence on whether the technology could deliver net-negative emissions at industrial scale.

Significant challenges remain before large-scale deployment would be possible. Researchers will need to identify affordable and environmentally responsible sources of olivine or other suitable silicate minerals.

Scientists are also investigating whether valuable metals released during mineral processing could be recovered. If feasible, metal extraction could potentially create additional economic value alongside carbon sequestration.

Large seawater basins could support future deployment

One possible future design would use large basins resembling infrastructure already found at wastewater treatment facilities.

Engineered bacteria could be cultivated inside these systems while untreated seawater is pumped through basins containing silicate minerals. The microorganisms would help maintain exposed mineral surfaces and accelerate weathering.

After treatment, more alkaline seawater containing carbon stored primarily in dissolved bicarbonate could be returned to the ocean.

Such facilities could potentially be established in coastal areas where large quantities of seawater are readily accessible.

Although considerably more research, environmental assessment, and engineering development will be required, the study suggests that genetically engineered marine bacteria could eventually become part of a broader portfolio of carbon dioxide removal technologies.

By combining synthetic biology with enhanced rock weathering, scientists are exploring whether one of Earth’s oldest carbon-regulating mechanisms can be accelerated enough to contribute meaningfully to modern climate mitigation efforts.I can also prepare the SEO title, meta description, and a title shortened to 50 characters for this article.