A novel CO2 steady feeding based on the pH steady strategy data in the Haematococcus pluvialis cultivation to maximize the cell growth and carbon bio-sequestration

Two common strategies to feed the CO2 are pH steady (PS) and CO2 steady (CS). An innovative strategy called "CSBPS (CS feeding based on PS data)" in comparison to the 0.04% CS, 5% CS, and PS approaches improved the Haematococcus pluvialis growth and carbon bio-sequestration. The optimum concentration of CO2 was estimated based on the PS cultivation data and fed to culture media using the CS approach with no buffering agent. The biomass productivity, CO2 bio-fixation rate, and rubisco activity under CSBPS strategy were 127, 121, and 65% higher than 0.04% CS strategy, respectively. The DIC concentration 177-230 (mg/L) and C/N ratio 0.48-0.76 were found promising for cell growth through increasing the rubisco activities under CSBPS strategy by 65, 54 and, 4% higher than 0.04% CS, 5% CS and PS strategies, respectively. The presented strategy provides a promising eco-friendly approach to reduce the CO2 losses and the production cost.