Engineered marine bacteria accelerate rock weathering for atmospheric carbon removal
核心洞察
Harvard-led researchers engineered the marine bacterium Alteromonas macleodii (搜索) to continuously produce the siderophore petrobactin (搜索), decoupling production from environmental iron levels.
The engineered microbes increased olivine (搜索) dissolution 2.6-fold in small seawater reactors and 3.1-fold in pilot-scale reactors compared with abiotic controls.
Pilot reactors containing over 4 kg of olivine (搜索) and raw Boston Harbor seawater generated alkalinity equivalent to removing about 0.5 g of atmospheric CO2 per day.
Researchers have engineered a widespread marine bacterium to speed up rock weathering, a natural process that pulls carbon dioxide from the atmosphere, offering a potential synthetic-biology route to enhanced carbon removal. The work, led by scientists from Harvard University's Wyss Institute, Harvard Medical School, and the Stanford Doerr School of Sustainability (搜索), modified Alteromonas macleodii (搜索) to continuously produce siderophores—molecules microbes use to scavenge iron—thereby accelerating the dissolution of the silicate mineral olivine (搜索) in seawater.
The study was published in Nature Biotechnology (2026, DOI: 10.1038/s41587-026-03288-w).
Overcoming the rust barrier to weathering
Rock weathering begins when silicate minerals such as olivine (搜索) dissolve after exposure to water, air, and biological activity. The process releases magnesium, iron, and silicate while converting atmospheric CO2 dissolved in water into bicarbonate. However, the released iron oxidizes when exposed to the atmosphere and forms rust over the mineral surface, a coating that slows further dissolution and limits the rate at which the rock can capture carbon.
"These rocks rust almost immediately," said Neil Dalvie, a Harvard Medical School chemical engineer and the study's first author. As olivine (搜索) dissolves, it releases Fe(II), which oxidizes to Fe(III) in oxygenated water. Iron oxides then precipitate onto the mineral surface, inhibiting further dissolution. Siderophores can bind Fe(III), keeping the iron soluble and helping prevent this buildup.
Engineering continuous siderophore production
The researchers used Alteromonas macleodii (搜索), a marine bacterium abundant in seawater that naturally produces the siderophore petrobactin (搜索). However, bacteria typically make siderophores only when iron is scarce—a condition not met inside a reactor packed with iron-containing olivine (搜索).
"To enable enhanced weathering at scale, we engineered A. macleodii to always produce siderophores. We essentially decoupled siderophore production from environmental iron levels," said Dalvie.
The genetic modification increased olivine (搜索) dissolution 2.6-fold in small seawater reactors compared with an abiotic control.
Pilot-scale reactors capture carbon from air
The team then scaled the system to reactors containing more than 4 kg of construction-grade olivine (搜索) and unprocessed seawater from Boston Harbor. Under steady-state conditions, with seawater and bacteria continuously flowing over the mineral, the engineered bacteria increased magnesium release—a measure of olivine dissolution—by a factor of 3.1 compared with the control.
The additional alkalinity generated was equivalent to removing about 0.5 g of atmospheric CO2 per day.
"Our study embraces the concept of biologically inspired engineering and how synthetic biology can be applied to enhance normal climate-regulating processes, which ultimately could have a positive impact on our planet," said Pamela Silver, a founding core faculty member at the Wyss Institute (搜索).
Toward industrial deployment
The researchers envision eventually flowing seawater through large reactors containing crushed rock and engineered microbes, then returning the alkaline water to the ocean. One proposed deployment would involve growing the engineered bacteria in large basins similar to those used at sewage treatment facilities.
The team also completed a life-cycle analysis covering carbon captured and emitted across the biological, geological, and chemical components of the system, which helped identify operating parameters important for achieving net carbon removal at an industrial scale.
Further work is needed. After several weeks, biofilms and a hardened mineral crust accumulated on the olivine (搜索), potentially creating new barriers to weathering. Researchers are also studying whether valuable metals could be recovered from the minerals while carbon is sequestered, and further research is needed to locate economically viable sources of silicate minerals and other feedstocks.