Nonphotosynthetic Biological CO₂ Reduction

Alarming changes in environmental conditions have prompted significant research into producing renewable commodities from sources other than fossil fuels. One such alternative is CO₂, a determinate greenhouse gas with historically high atmospheric levels. If sequestered, CO₂ could be used as a highly renewable feedstock for industrially relevant products and fuels. The vast majority of atmospheric CO₂ fixation is accomplished by photosynthetic organisms, which have unfortunately proven difficult to utilize as chassis for industrial production. Nonphotosynthetic CO₂ fixing microorganisms and pathways have recently attracted scientific and commercial interest. This Perspective will review promising alternate CO₂ fixation strategies and their potential to supply microbially produced fuels and commodity chemicals, such as higher alcohols. Acetogenic fermentation and microbial electrosynthesis are the primary focuses of this review.