Atmospheric CO2 concentration has been rising since the Industrial Revolution and is predicted to double by the end of this century. Microalgae play an important role in the carbon cycle of marine ecosystems and their responses to elevated atmospheric CO2 are of considerable interest. The effects of CO2 enrichment are variable and may depend on the availability of nutrients, since CO2 supply leads to a higher growth rate and to an increased demand for nutrients. CO2 released by industrial activities contributes substantially to increase the atmospheric CO2 level; thus it is becoming more and more important to find alternatives to control its release in the atmosphere. Flue gases produced by processes such as anaerobic digestion, for instance, could be potentially used for microalgae culturing, thus preventing their release and allowing the transformation of polluting gas fluxes into new and valuable microalgae products. In this study physiological responses to CO2 supply in two microalgal species that have potential industrial applications were investigated. In particular Desmodesmus communis, a green algae widely used for phycoremediation due to its high resistance to chemical and environmental stress, and the diatom Phaeodactylum tricornutum, a PUFAs producer widely used in aquaculture, were studied using 1 L batch cultures or 70 L photobioreactors. Flue gases obtained by anaerobic digestion and enriched in CO2 by the removal of the biogas fraction were also tested for microalgae culturing. Results showed a marked increase of the growth and productivity in cultures with CO2 addition respect to the ones grown with only air. Moreover, a different use of macronutrients by algal cells and changes in cellular composition were observed when CO2 was supplied. Preliminary experiments performed using flue gases supplied to P. tricornutum cultures reported no inhibition of the algal growth and promising results attesting their potential use to cultivate microalgae.

Effect of CO2 supply on the growth and nutrient uptake in microalgae cultures for industrial applications

Silvana Vanucci;
2017-01-01

Abstract

Atmospheric CO2 concentration has been rising since the Industrial Revolution and is predicted to double by the end of this century. Microalgae play an important role in the carbon cycle of marine ecosystems and their responses to elevated atmospheric CO2 are of considerable interest. The effects of CO2 enrichment are variable and may depend on the availability of nutrients, since CO2 supply leads to a higher growth rate and to an increased demand for nutrients. CO2 released by industrial activities contributes substantially to increase the atmospheric CO2 level; thus it is becoming more and more important to find alternatives to control its release in the atmosphere. Flue gases produced by processes such as anaerobic digestion, for instance, could be potentially used for microalgae culturing, thus preventing their release and allowing the transformation of polluting gas fluxes into new and valuable microalgae products. In this study physiological responses to CO2 supply in two microalgal species that have potential industrial applications were investigated. In particular Desmodesmus communis, a green algae widely used for phycoremediation due to its high resistance to chemical and environmental stress, and the diatom Phaeodactylum tricornutum, a PUFAs producer widely used in aquaculture, were studied using 1 L batch cultures or 70 L photobioreactors. Flue gases obtained by anaerobic digestion and enriched in CO2 by the removal of the biogas fraction were also tested for microalgae culturing. Results showed a marked increase of the growth and productivity in cultures with CO2 addition respect to the ones grown with only air. Moreover, a different use of macronutrients by algal cells and changes in cellular composition were observed when CO2 was supplied. Preliminary experiments performed using flue gases supplied to P. tricornutum cultures reported no inhibition of the algal growth and promising results attesting their potential use to cultivate microalgae.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/3144827
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