Enhanced CO2 fixation and biofuel production via microalgae: recent developments and future directions

Unbalanced production of atmospheric CO2 constitutes a major challenge to global sustainability. Technologies have thus been developed for enhanced biological carbon fixation (also referred to as CO2 mitigation), and one of the most promising capitalizes on microalgae. However, the “best bioreactor”, which would be able to achieve maximum productivity and maximum energy efficiency under a given set of operational costs, does not exist. This review briefly examines the current technologies available for enhanced microalgal CO2 fixation, and specifically explores the possibility of coupling wastewater treatment with microalgal growth for eventual production of biofuels and/or added-value products, with an emphasis on productivity. In addition, an overview of reactor configurations for CO2 fixation and bottlenecks associated with the underlying technology are provided. Finally, a review of life cycle analysis studies is presented, and routes for improvement of existing processes are suggested.