Engineered marine bacteria accelerated olivine weathering in bioreactors

Researchers at Harvard and Stanford engineered the marine bacterium Alteromonas macleodii to keep producing siderophores, molecules that remove iron from silicate-mineral surfaces. In continuous-flow seawater bioreactors, the team reported a 2.6-fold increase in olivine weathering and higher carbon-dioxide removal. Pilot-scale reactors containing several kilograms of olivine sand reportedly captured 0.5 grams of atmospheric CO2 per day. The results were published in Nature Biotechnology, but the researchers say further scale-up work is needed to identify economical feedstocks and minerals.