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.