Reuniting the Biogeochemistry of Algae for a Low-Carbon Circular Bioeconomy

Given their advantages of high photosynthetic efficiency and non-competition with land-based crops, algae, that are carbon-hungry and sunlight-driven microbial factories, are a promising solution to resolve energy crisis, food security, and pollution problems. The ability to recycle nutrient and CO2 fixation from waste sources makes algae a valuable feedstock for biofuels, food and feeds, biochemicals, and biomaterials. Innovative technologies such as the bicarbonate-based integrated carbon capture and algae production system (BICCAPS), integrated algal bioenergy carbon capture and storage (BECCS), as well as ocean macroalgal afforestation (OMA), can be used to realize a low-carbon algal bioeconomy. We review how algae can be applied in the framework of integrated low-carbon circular bioeconomy models, focusing on sustainable biofuels, low-carbon feedstocks, carbon capture, and advances in algal biotechnology. Algae are promising players in the framework of an integrated circular bioeconomy.Wastewater and flue gas are alternative low-carbon feedstocks for algae cultivation.Bicarbonate-based integrated carbon capture and algae production system (BICCAPS), integrated algal bioenergy carbon capture and storage (BECCS), and ocean macroalgal afforestation (OMA) are algae-based carbon-capture technologies.The evolution of the biotechnology industry and government policies are promoting the growth of bioeconomies.