Novel Regeneration and Utilization Concept Using Rich Chemical Absorption Solvent As a Carbon Source for Microalgae Biomass Production

Integration of chemical absorption and microalgae bioconversion is a promising alternative to overcome the low CO2 fixation efficiency of conventional microalgae CO2 fixation technologies. In this study, two different bicarbonate sources obtained from ammonia and potassium carbonate CO2 absorption processes were used as carbon sources to cultivate Chlorella sp. L38, and different feeding modes were investigated. The experimental results indicated that the biomass concentration could be enhanced (up to 0.6 g/L) by using bicarbonate as carbon source instead of CO2. Particularly, nitrogen and carbon fixation capacity could achieve 48 mg/L and 49 mg/L/d with a carbon fixation efficiency over 60% when using NH4HCO3 as a carbon and nitrogen source. Additionally, the protein, polysaccharides and lipid yields achieved 298, 12.5, and 59 mg/L, respectively, and were higher than the control condition. It could be observed that using bicarbonate as a linkage to integrate CO2 absorption and bioconversion may be a promising alternative to the conventional CO2 capture technologies.