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

The aim of this study was to evaluate the influence of different carbon dioxide (CO2 ) concentrations on the distribution of carbon forms in the culture medium and the biomass production and biomolecules productivity of the strain Chlorella fusca LEB 111. In this study, experiments were carried out in which C. fusca cultures were exposed to different CO2 concentrations, 0.03% (0.08 mlCO2 mlmedium -1 days-1 ), 5% (0.18 mlCO2 mlmedium -1 days-1 ), and 15% vol/vol CO2 (0.54 mlCO2 mlmedium -1 days-1 ). Among the carbon chemical species distributions in the culture medium, bicarbonate was predominant (94.2-98.9%), with the highest quantitative percentage in the experiment receiving a 15% CO2 injection. C. fusca LEB 111 cultivated with 15% CO2 showed the highest biomass productivity (194.3 mg L-1 days-1 ) and CO2 fixation rate (390.9 mg L-1 days-1 ). The carbohydrate productivity in the culture that received 15% CO2 was 46.2% higher than the value verified for the culture with the addition of CO2 from the air (0.03% CO2 ). In addition, CO2 concentration providing increases of 0.03-15% to C. fusca cultures resulted in a 31.6% increase in the lipid productivity. These results showed that C. fusca can be used for CO2 bioconversion and for producing biomass with potential applications for biofuels and bioproducts.