Genetically engineered marine bacteria accelerate carbon dioxide removal 2.6-fold

Genetically engineered marine bacteria accelerated rock weathering 2.6-fold, increasing the rate of carbon dioxide removal from the atmosphere.

According to Azolife Sciences on the 31st (local time), a joint research team from the Wyss Institute at Harvard University, Harvard Medical School and Stanford Doerr School of Sustainability genetically engineered the marine bacterium 'Alteromonas macleodii' to accelerate the weathering of silicate minerals.

The findings were published in the international journal Nature Biotechnology.

Rock weathering is the breakdown and dissolution of rocks and minerals exposed to water, air and living organisms, and is a key factor in regulating atmospheric carbon dioxide levels. In nature, however, the process takes hundreds of thousands of years, making it too slow to serve as a climate solution.

The research team engineered the bacteria to produce large quantities of a molecule called a 'siderophore,' which extracts iron from the silicate mineral olivine. In nature, when iron accumulates as rust on mineral surfaces, weathering slows; siderophores remove this rust, thereby promoting weathering.

First author Neil Dalby, Ph.D., said, "Wild bacteria completely stop producing siderophores when they have enough iron to grow. For large-scale weathering, we engineered them to keep producing siderophores regardless of the iron concentration in the environment."

The research team tested several kilograms of olivine sand in a pilot-scale bioreactor continuously supplied with seawater drawn from Boston Harbor. They confirmed that the reactor actually absorbed 0.5 g of atmospheric carbon dioxide per day.

The team also conducted a life-cycle assessment (LCA) to calculate the carbon balance across the entire process. Co-author Michael Springer, Ph.D., said, "The most direct environmental impact would come from growing the bacteria in large tanks similar to those at wastewater treatment plants, continuously feeding in untreated seawater, and then returning the carbon-bound alkaline seawater to the ocean."

Dalby recently received a Burroughs Wellcome Fund Career Award at the Scientific Interface (CASI) fellowship and plans to continue follow-up research on microbial siderophore production and mineral processing.