Green alga cultivation with monoethanolamine: Evaluation of CO2 fixation and macromolecule production

Bioprocess strategies for enhancing biomolecules productivity in Chlorella fusca LEB 111 using CO2 a carbon source

“…The protein concentration showed no significant difference ( p > .05) between the different CO 2 concentrations (5 and 15% CO 2 ). The protein concentration results obtained in the present study were similar to those verified by Rosa et al in C. fusca LEB 111 cultures under the control condition (38.1% wt/wt) and with the injection of CO 2 (0.36 ml CO2 ml medium −1 days −1 ) and the absorbent chemical monoethanolamine (MEA) at concentrations of 50 mg/L (32.2% wt/wt), 100 mg/L (32.1% wt/wt), and 150 mg/L (33.5% wt/wt).…”

“…The initial cell concentration was 0.2 g/L, and the culture medium was a modified BG‐11 without sodium carbonate (Na 2 CO 3 ). The experiments were carried out under fed‐batch with CO 2 , and stirring by compressed air bubbled through a sintered stone diffuser at a flow rate of 450 ml air /min . During the light period, the compressed air gas stream was enriched with different pure CO 2 concentrations, in which corresponding to a specific daily CO 2 flow rate of the 0.18 ml CO2 ml medium −1 days −1 (5.0% vol/vol) and 0.54 ml CO2 ml medium −1 days −1 (15% vol/vol).…”

“…The all gas flow rates were measured by rotameters (Cole Parmer). To increase the residence time of the carbon source in the medium, the stirring of the assays was stopped 1 min before and 1 min after the addition of CO 2 to the culture . Two control assays were carried out with stirring by atmospheric air and: (a) standard BG‐11 medium; (b) BG‐11 medium without Na 2 CO 3 , in this one the CO 2 of atmospheric air (0.03% vol/vol CO 2 –0.08 ml CO2 ml medium −1 days −1 ) was the unique carbon source.…”

“…The biomass was then resuspended in distilled water and centrifuged again under the same conditions to remove the nutrient salts. The concentrated biomass was further frozen at −80°C for 48 hr, lyophilized (Labconco) and then stored at −20°C …”

“…The productivity of the carbohydrates and lipids ( P biomolecule , mg L −1 days −1 ) was determined according to the following equation: P biomolecule = P final ∙ f biomolecule , where P x (mg L −1 days −1 ) is the final biomass productivity and f biomolecule (g biomolecule /g biomass ) expresses the mass of the biomolecule of interest per gram of biomass …”