Strategies to improve viability of a circular carbon bioeconomy-A techno-economic review of microbial electrosynthesis and gas fermentation

Valorisation of CO2 into Value-Added Products via Microbial Electrosynthesis (MES) and Electro-Fermentation Technology

“…As seen in Table 3. the acetogen Sporomosa ovata, a close relative to M. thermoacetica was able to directly accept e − from the cathode and transform CO 2 to acetate and 2-oxobutyrate, whereas A. woodii, was unable to do so as it lacked Cyt c and relies upon the sodium gradient which is coupled to the WL pathway, thereby, reflecting a different behaviour as compared to other acetogens in Nevins experiment [24,25,78].…”

“…via H 2 mediated e − transfer or DET. Generally, the acetogens employ the Wood-Ljungdahl (WL) pathway for CO 2 fixation and are used as biocatalysts at the cathode, yielding acetate as the chief MES product, nevertheless, other organic chemicals with more carbon content, like butyrate, caproate, ethanol, caprylate, propionate and isopropanol can also be produced [25,114,155].…”

“…An important microorganism used for this process is Clostridium ljungdahlii. Although pure cultures can be used for this process, even mixed cultures are an amazing alternative, as portrayed in Table 3 [25,145,165,166]. Apart from ethanol, butyrate and acetate, lactate and succinate can also be produced from intermediate products generated in the system via the Krebs cycle.…”

“…The best solution to the present-day challenges including resource scarcity, waste generation and sustaining economic benefits is an economy that is environmentally and economically regenerative like that of a circular bio-based economy depicted by MES [8,25,114]. Using alternative energy resources for the generation of biofuel are becoming an increasing trend.…”

“…acetogenic bacteria gain electrons from graphite electrodes and act as an electron (e − ) donor in the reduction of CO 2 -producing multi-carbon compounds extracellularly. A strain named Clostridium ljungdahlii is capable of MES, which can be genetically controlled and can be used to generate high-valued commodities [21][22][23][24][25].…”