Researchers at the Wyss Institute at Harvard University, Harvard Medical School, and the Stanford Doerr School of Sustainability have engineered bacterial siderophore production to accelerate rock weathering for carbon removal, according to a study published in Nature Biotechnology. The team genetically modified the widespread marine bacterium Alteromonas macleodii to produce high amounts of iron-extracting molecules called siderophores, speeding up the breakdown of the silicate mineral olivine by 2.6-fold in custom bioreactors.
How Synthetic Biology Accelerates Natural Rock Weathering
Rock weathering is a slow geological process that regulates Earth’s atmospheric carbon dioxide levels over hundreds of thousands of years. When minerals like olivine break down and dissolve upon exposure to water and air, they trap atmospheric carbon dioxide in the water as bicarbonate. However, natural weathering hits a major bottleneck. According to Wyss Institute researchers, iron released during the dissolution process is insoluble when exposed to the atmosphere, covering the mineral surface as rust and halting further breakdown.
To overcome this limitation, chemical engineer Neil Dalvie and his colleagues targeted siderophores—natural compounds that bacteria use to capture, solubilize, and take up rusted iron. In laboratory tests using custom rock-seawater bioreactors, natural bacteria stopped producing siderophores as soon as they encountered enough iron to sustain their growth. By using synthetic biology to force Alteromonas macleodii to continually produce these molecules, the engineered strains stripped the rust from the mineral surfaces, sustaining rapid dissolution and accelerating carbon capture.
Scaling Up Enhanced Rock Weathering for Industrial Decarbonization
While companies globally pursue enhanced rock weathering by scattering crushed silicate rocks on agricultural fields or directly into water, the natural timeline remains too slow to significantly impact the global carbon balance at an industrial scale. The collaborative research team, led by Wyss Institute Founding Core Faculty member Pamela Silver and Associate Faculty member Michael Springer, aims to bridge that gap. Silver noted in a Wyss Institute statement that the strategy applies synthetic biology to enhance natural climate-regulating processes for real-world decarbonization outcomes.
The research was supported by the Synthetic Biology Hive at Harvard Medical School. The team’s continuous-flow seawater bioreactors demonstrated that targeted biological intervention can bypass the chemical barriers that usually stall mineral dissolution, offering a scalable pathway for marine-based carbon removal.
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