The chemical absorption of carbon dioxide (CO2) is a technique used for the mitigation of the greenhouse effect. However, this process consumes high amounts of energy to regenerate the absorbent and to separate the CO2. CO2 removal by microalgae can be obtained via the photosynthesis process. The objective of this study was to investigate the cultivation and the macromolecules production by Spirulina sp. LEB 18 with the addition of monoethanolamine (MEA) and CO2. In the cultivation with MEA, were obtained higher results of specific growth rate, biomass productivity, CO2 biofixation, CO2 use efficiency, and lower generation time. Besides this, the carbohydrate concentration obtained at the end of this assay was approximately 96.0% higher than the control assay. Therefore, Spirulina can be produced using medium recycle and the addition of MEA, thereby promoting the reduction of CO2 emissions and showing potential for areas that require higher concentrations of carbohydrates, such as in bioethanol production.

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The objective of this study was to select a concentration of CO2 absorbents to supplement Spirulina sp. LEB 18 cultivation and to evaluate the effect of these compounds on the growth and production of macromolecules. Three initial biomass concentrations (X0), eight concentrations of monoethanolamine (MEA), and three NaOH concentrations were tested. The selected MEA concentrations did not inhibit the growth of Spirulina and doubled the dissolved inorganic carbon concentration in the assay medium in relation to the concentration of NaOH. The protein concentration in the biomass grown with MEA was, on average, 17% higher than that obtained with NaOH. Thus, it was found that MEA did not reduce the productivity of Spirulina sp. LEB 18, and its use can be further explored as a means for converting the carbon dissolved in the medium to biomolecules.

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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.