Industrial carbon capture technologies are almost universally built
around freshwater systems — an assumption so deeply embedded that
salinity is treated as a contaminant to be removed rather than a
resource to be used. This work asks: what happens if we build with salt
instead of around it?

We investigated halophilic, CO₂-fixing microbial communities as
biocatalysts in microbial electrosynthesis (MES) — a bioelectrochemical
process where electrical current powers microbes to convert waste CO₂
into value-added chemicals. Using salt-tolerant organisms rather than
conventional freshwater-adapted ones, the process ran with improved
energy efficiency, while eliminating the freshwater dependency that
constrains most carbon-conversion systems today.

The implications extend beyond the lab bench. Saline and brackish waste
streams — seawater, industrial brine, desalination reject — are
abundant, under-used, and typically discarded as waste. A biocatalyst
that thrives on salinity rather than despite it opens the door to
carbon-conversion systems sited wherever salt water already exists,
rather than wherever fresh water can be spared.

This research presents the microbial and process-efficiency findings,
and invites discussion on where such salt-tolerant, circular
carbon-conversion approaches could be piloted next.