Effects of different bicarbonate on spirulina in CO₂ absorption and microalgae conversion hybrid system

According to the characteristics of power plant flue gas emission and the requirements of reducing CO₂ capture cost. CO₂ absorption hybrid with microalgae conversion (CAMC) can avoid the challenges of heat consumption during absorbent desorption and nutrient consumption during microalgae culture. In this study, the bicarbonate solution (represents the products of CO₂ absorption by Na₂CO₃ and K₂CO₃) is used as carbon source for mutagenic Spirulina platensis cultivation, and different concentrations of bicarbonate were set to explore the best carbon source. The results showed that NaHCO₃ was a better medium for the CO₂ absorption hybrid with microalgae conversion system, which was beneficial for the growth of mutagenic Spirulina, compared with K₂CO₃. When .3 mol/L NaHCO₃ was added to the CO₂ absorption hybrid with microalgae conversion system, the highest biomass dry weight, carbon fixation rate and carbon utilization efficiency were obtained, which were 2.24 g/L, 230.36 mg/L/d and 26.71%, respectively. In addition, .3 mol/L NaHCO₃ was conducive to protein synthesis, reaching 1,625.68 mg/L. This study provided a feasible idea for power system to achieve carbon neutrality in the future.