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Microalgae are one of the most promising sources of renewable substrates used for energy purposes. Biomass and components accumulated in their cells can be used to produce a wide range of biofuels, but the profitability of their production is still not at a sufficient level. Significant costs are generated, i.a., during the cultivation of microalgae, and are connected with providing suitable culture conditions. This study aims to evaluate the possibility of using sodium bicarbonate as an inexpensive alternative CO2 source in the culture of Chlorella vulgaris, promoting not only the increase of microalgae biomass production but also lipid accumulation. The study was carried out at technical scale using 100 L photobioreactors. Gravimetric and spectrophotometric methods were used to evaluate biomass growth. Lipid content was determined using a mixture of chloroform and methanol according to the Blight and Dyer method, while the carbon content and CO2 fixation rate were measured according to the Walkley and Black method. In batch culture, even a small addition of bicarbonate resulted in a significant (p ≤ 0.05) increase in the amount of biomass, productivity and optical density compared to non-bicarbonate cultures. At 2.0 g∙L–1, biomass content was 572 ± 4 mg·L−1, the maximum productivity was 7.0 ± 1.0 mg·L–1·d–1, and the optical density was 0.181 ± 0.00. There was also an increase in the lipid content (26 ± 4%) and the carbon content in the biomass (1322 ± 0.062 g∙dw–1), as well as a higher rate of carbon dioxide fixation (0.925 ± 0.073 g·L–1·d–1). The cultivation of microalgae in enlarged scale photobioreactors provides a significant technological challenge. The obtained results can be useful to evaluate the efficiency of biomass and valuable cellular components production in closed systems realized at industrial scale.
Patryk Ratomski; Małgorzata Hawrot-Paw; Adam Koniuszy. Utilisation of CO2 from Sodium Bicarbonate to Produce Chlorella vulgaris Biomass in Tubular Photobioreactors for Biofuel Purposes. Sustainability 2021, 13, 9118 .
AMA StylePatryk Ratomski, Małgorzata Hawrot-Paw, Adam Koniuszy. Utilisation of CO2 from Sodium Bicarbonate to Produce Chlorella vulgaris Biomass in Tubular Photobioreactors for Biofuel Purposes. Sustainability. 2021; 13 (16):9118.
Chicago/Turabian StylePatryk Ratomski; Małgorzata Hawrot-Paw; Adam Koniuszy. 2021. "Utilisation of CO2 from Sodium Bicarbonate to Produce Chlorella vulgaris Biomass in Tubular Photobioreactors for Biofuel Purposes." Sustainability 13, no. 16: 9118.
Microalgal biomass and its cellular components are used as substrates for the production of fuels. A valuable group among the components of microalgal biomass is lipids, which act as a precursor for the production of biodiesel in the transesterification process. Some methods, including the creation of stressful conditions, are applied to increase the accumulation of lipids. This study aimed to determine the effect of limited nutrient access on the growth and development of the microalga Chlorella vulgaris and the amount of lipids stored in its cells. Aquaculture wastewater (AWW) was used in the study as a source of nutrients at doses of 20%, 40%, 60%, 80% and 100%. The amount of microalgal biomass, optical density, lipid content after extraction of the biomass in Soxhlet apparatus and chlorophyll a content were determined. It was observed that the microalgae efficiently used the nutrients contained in the AWW. The largest amount of biomass was obtained in AWW80 (727 ± 19.64 mg·L−1). The OD680 (0.492 ± 0.00) determined under the same conditions was almost five times higher in AWW than in the synthetic medium. Under nutrient-stress conditions, the content of lipids in biomass ranged from 5.75% (AWW80) to 11.81% (AWW20). The highest content of chlorophyll a in microalgal cells was obtained in AWW20 (206 ± 11.33 mg∙m−3).
Patryk Ratomski; Małgorzata Hawrot-Paw. Influence of Nutrient-Stress Conditions on Chlorella vulgaris Biomass Production and Lipid Content. Catalysts 2021, 11, 573 .
AMA StylePatryk Ratomski, Małgorzata Hawrot-Paw. Influence of Nutrient-Stress Conditions on Chlorella vulgaris Biomass Production and Lipid Content. Catalysts. 2021; 11 (5):573.
Chicago/Turabian StylePatryk Ratomski; Małgorzata Hawrot-Paw. 2021. "Influence of Nutrient-Stress Conditions on Chlorella vulgaris Biomass Production and Lipid Content." Catalysts 11, no. 5: 573.
Biomass of microalgae and the components contained in their cells can be used for the production of heat, electricity, and biofuels. The aim of the presented study was to determine the optimal conditions that will be the most favorable for the production of large amounts of microalgae biomass intended for energy purposes. The study analyzed the effect of the type of lighting, the time of lighting culture, and the pH of the culture medium on the growth of Chlorella vulgaris biomass. The experiment was carried out in vertical tube photobioreactors in three photoperiods: 12/12, 18/6, and 24/0 h (light/dark). Two types of lighting were used in the work: high-pressure sodium light and light-emitting diode. The increase in biomass was determined by the gravimetric method, by the spectrophotometric method on the basis of chlorophyll a contained in the microalgae cells. The number of microalgae cells was also determined with the use of a hemocytometer. The optimal conditions for the production of biomass were recorded at a neutral pH, illuminating the cultures for 18 h a day. The obtained results were 546 ± 7.88 mg·L−1 dry weight under sodium lighting and 543 ± 1.92 mg·L−1 dry weight under light-emitting diode, with maximum biomass productivity of 27.08 ± 7.80 and 25.00 ± 5.1 mg·L−1∙d−1, respectively. The maximum content of chlorophyll a in cells was determined in the 12/12 h cycle and pH 6 (136 ± 14.13 mg∙m−3) under light-emitting diode and 18/6 h, pH 7 (135 ± 6.17 mg∙m−3) under sodium light, with maximum productivity of 26.34 ± 2.01 mg·m−3∙d−1 (light-emitting diode) and 24.21 ± 8.89 mg·m−3∙d−1 (sodium light). The largest number of microalgae cells (2.1 × 106) was obtained at pH 7 and photoperiod of 18/6 h under sodium light, and 12/12 h under light-emitting diode. Based on the results, it can be concluded that the determination of the optimal parameters for the growth and development of microalgae determines the production of their biomass, and such research should be carried out before starting the large-scale production process. In quantifying the biomass during cultivation, it is advantageous to use direct measurement methods.
Patryk Ratomski; Małgorzata Hawrot-Paw. Production of Chlorella vulgaris Biomass in Tubular Photobioreactors during Different Culture Conditions. Applied Sciences 2021, 11, 3106 .
AMA StylePatryk Ratomski, Małgorzata Hawrot-Paw. Production of Chlorella vulgaris Biomass in Tubular Photobioreactors during Different Culture Conditions. Applied Sciences. 2021; 11 (7):3106.
Chicago/Turabian StylePatryk Ratomski; Małgorzata Hawrot-Paw. 2021. "Production of Chlorella vulgaris Biomass in Tubular Photobioreactors during Different Culture Conditions." Applied Sciences 11, no. 7: 3106.