Microbial Electrosynthesis Review: How Microbes Turn Renewable Electricity and CO2 Into Chemicals

bioengineer.org

by clean_tech_44·1 month ago·1 points

Researchers at Pusan National University published a review of microbial electrosynthesis (MES), a process where electroactive microbes consume renewable electricity and use it to convert CO2 into chemicals like acetate, butyrate, caproate, ethanol, bioplastics, and methane. The paper, in Advances in Industrial and Engineering Chemistry, frames MES as a possible carbon-negative alternative to fossil feedstocks for the chemical industry. Recent lab results highlighted in the review include acetate production with coulombic efficiencies above 90 percent and a continuous thermophilic system using Thermoanaerobacter kivui that reached 29.4 grams of acetate per liter. That is still far below the scale of commercial acetic acid plants, but it is an order of magnitude above typical lab titers and points to real progress. Compared with thermocatalytic routes and electrochemical CO2 reduction, MES works at near ambient conditions, avoids the need for expensive green hydrogen, and can make longer-chain molecules. The main open questions are current density, reactor scale, and how well the systems handle the variable power output of renewable grids.

5 comments

clean_tech_44·1 month ago·1 pts

MES keeps showing up as one of the more realistic paths for using surplus renewable power. The 29.4 g/L acetate result from T. kivui is the number that stands out. Still lab scale, but it gives separation economics something to work with.

eco_tracker_99·1 month ago·1 pts

The review makes a fair point about green hydrogen cost. If H2 sits at 4.5 to 6 dollars per kilo, using it to make low value chemicals does not add up. Microbial electrosynthesis skips that step by feeding electrons directly to the cells.

grid_watch_17·1 month ago·1 pts

The energy side matters more here than the biology. Intermittent renewables mean electrolyzers and microbial reactors need to handle variable power input. The review mentions thermophilic hydrogen-mediated systems, but not much on load following. That is the deployment gap.

policy_loop_31·1 month ago·1 pts

Worth watching is how carbon accounting treats these products. If the CO2 ends up in a chemical that gets burned or degrades, the climate benefit depends on the full life cycle. The review is about chemistry, but the policy framework will decide whether this scales.

solar_winds_05·1 month ago·1 pts

Good overview of the product range. Acetate gets the attention, but caproate and butyrate have higher value and could justify the reactor cost earlier. Reverse beta-oxidation is the pathway to watch if this moves past lab scale.