Thermal cultivation of halophilic Cyanobacterium aponinum for C-phycocyanin production and simultaneously reducing carbon emission using wastewater

A newly halophilic Cyanobacteria aponinum PCC10605 is first explored as a robust blue alga compared to Chlorella sorokiniana (CS), Chlorella vulgaris (CV) and Chlamydomonas reinhardtii (CC400) that can be cultured at high salinity and mesophilic condition. The Logistic and Gompertz models were applied to evaluate cell growth of four algal strains under mixotrophic and autotrophic cultivation, thus the optimal condition for PCC10605 was indicated in autotrophic and 20 g/L seawater at 39 degrees C. When nitrogen and phosphorus concentration was at the ratio of 3:1, PCC10605 grew fast and had the better C-phycocyanin (C-PC) productivity, achieving to 1.53 g/L of biomass and 0.492 g/L of C-PC under 25% light intensity and 12:12 light period. Finally, a feasible and negative carbon emission via PCC10605 which cultured in the mixed medium and wastewater at 1:2 vol ratio (i.e., M1W2), reaching to 1.227 g/L of biomass concentration, 0.503 g/L C-PC production, reducing 40.5% of chemical oxygen demand (COD), and capturing 1.71 g-CO2 simultaneously in a Photo System Instruments (PSI).

Automated summary

The newly discovered halophilic Cyanobacteria aponinum PCC10605 shows robust growth as a blue alga, compared to other strains such as Chlorella sorokiniana, Chlorella vulgaris, and Chlamydomonas reinhardtii. The optimal conditions for PCC10605 cultivation were found to be autotrophic growth in 20 g/L seawater at 39 degrees C. When the nitrogen and phosphorus concentration was at a ratio of 3:1, PCC10605 showed fast growth and higher C-phycocyanin (C-PC) productivity. It achieved a biomass concentration of 1.53 g/L and C-PC production of 0.492 g/L under 25% light intensity and a 12:12 light period. Additionally, PCC10605 demonstrated the potential for negative carbon emissions when cultured in a mixed medium and wastewater with a 1:2 vol ratio, reducing 40.5% of chemical oxygen demand (COD) and simultaneously capturing 1.71 g-CO2.