Efficient and scalable upcycling of oceanic carbon sources into bioplastic monomers

Renewable electricity-driven capture and conversion of oceanic dissolved inorganic carbon into value-added chemicals offers a sustainable route towards negative carbon emissions and a circular carbon economy. Here we present an artificial ocean carbon recycling system that captures and converts oceanic carbon sources into biochemicals through a decoupled electro-biocatalytic hybrid process. The system captures CO 2 from natural seawater under very dilute yet realistic dissolved inorganic carbon conditions (2.16 mM) with high capture efficiency (>70%), low energy consumption (3 kWh kgCO 2 −1 ) and long stability (536 h). Techno-economic analysis revealed a competitive cost of capture (US$229.9 tCO 2 −1 ). Using a highly efficient and stable bismuth-based electrocatalyst, CO 2 was further converted into pure formic acid (800 mA cm −2 at −1.37 V) and subsequently transformed by engineered Vibrio natriegens into succinic acid (1.37 g l −1 ). Therefore, our electro-bioconversion system represents a solution to sustainable biochemical synthesis using the ocean carbon sink as a resource.