Opportunities of CO2-based biorefineries for production of fuels and chemicals

Biorefinery production of fuels and chemicals represents an attractive route for solving current energy crisis, as well as reducing green-house gas (GHG) emissions from ships, planes, and long-haul trucks. The current biorefinery industry is under transition from the use of food (1 G, 1st generation), to the use of biomass (2 G, 2nd generation). Moreover, the use of atmospheric CO2 (3 G, 3rd generation) has caught increased attention as the possible next-generation biorefinery. Here we discuss how microorganisms can be engineered for CO2-based biorefineries to produce fuels and chemicals. We start through reviewing different metabolic pathways that can be recruited for CO2 fixation, followed by different opportunities for CO2 fixation, either through co-consumption with sugars or used as the sole carbon source. Key challenges and future research directions for advancing 3rd-generation biorefineries are also be discussed.