Advances in cathode designs and reactor configurations of microbial electrosynthesis systems to facilitate gas electro-fermentation.

In gas fermentation, a range of chemolithoautotrophs fix single-carbon (C1) gases (CO and CO) when H or other reductants are available. Microbial electrosynthesis (MES) enables CO reduction by generating H or reducing equivalents with the sole input of renewable electricity. A combined approach as gas electro-fermentation is attractive for the sustainable production of biofuels and biochemicals utilizing C1 gases. Various platform compounds such as acetate, butyrate, caproate, ethanol, butanol and bioplastics can be produced. However, technological challenges pertaining to the microbe-material interactions such as poor gas-liquid mass transfer, low biomass and biofilm coverage on cathode, low productivities still exist. We are presenting a review on latest developments in MES focusing on the configuration and design of cathodes that can address the challenges and support the gas electro-fermentation. Overall, the opportunities for advancing CO and CO-based biochemicals and biofuels production in MES with suitable cathode/reactor design are prospected.