Bubble column photobioreactor (BCPR) for cultivating microalgae and microalgal consortium (Co-CC) with additional CO supply for enhancing biomass, lipid, and preferable fatty acids production.

The present study has designed and developed a 5 L bubble column photobioreactor (BCPR) to investigate two microalgal strains Chlorella sp. S-01, Chlorella sp. S-02 and their consortium Co-CC (Chlorella sp. S-01 + Chlorella sp. S-02) at 0.03, 5, and 10% CO supply for biomass and lipid production. The dry cell weight of Chlorella sp. S-01, Chlorella sp. S-02 and Co-CC were, respectively about 1.41, 1.32, and 1.39 g/L on the 20th day without CO supply, while it was 1.76, 1.61, and 1.87 g/L, respectively at 10% CO supply and similarly, chlorophyll-a content was higher in 10% CO supplied condition over control. Interestingly, Co-CC grown at all the CO concentrations showed similar lipid content between 19.30 and 1F9.41%. As an integrated refinery approach, de-oiled biomass of Co-CC was subjected to carbohydrates and protein estimation and found that 46.2% and 30.80% in 10% CO supply condition in BCPR. Lipid extracted from the Co-CC grown under 0.03, 5, and 10% CO supply in 5L BCPR was converted to biodiesel, and the biodiesel yield was estimated to be 62.78%. Further, the fatty acid profile of Co-CC grown at 10% CO showed higher levels of C16:0, C16:1, C18:1, and monounsaturated fatty acids contents over other CO supplied conditions. Biodiesel of Co-CC showed favourable fuel properties such as density, higher heating value, oxidative stability, CFPP, viscosity, degree of unsaturation, saponification value, and cetane number, which were also in accordance with ASTM, and EN, biodiesel standards.