Abreu, Ana Paula

Dragone, Giuliano

Fernandes, Bruno Daniel

Teixeira, J. A.

Vicente, A. A.

Universidade do Minho: RepositoriUM

Evaluation of the effect of mixotrophic growth on Chlorella vulgaris composition

Evaluation of the effect of mixotrophic growth on Chlorella vulgaris compositionJ.A. Teixeira1, A.P. Abreu2, G. Dragone2, B. Fernandes2, A. Vicente31 IBB – Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho2 IBB - Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar. 4710-057, Braga, Portugal.3 IBB - Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of MinhoMany microalgae such as Chlorella grow in mixotrophic conditions, using light as an energy source for the assimilation of organic carbon substrates, photosynthetic fixation of carbon dioxide and as an inducer for the formation of valuable algal products. Mixotrophy can overcome problems associated with the growth of phototrophic algae like light limitation at high cell densities and dark coloured (opaque) wastewaters. The aim of this study was to evaluate the influence of mixotrophy in cellular composition of Chlorella vulgaris and conclude about the feasibility of using this regime to obtain microalgal biomass. All culture experiments were performed at 30 ºC in 500 mL bubble columns photobioreactors containing 400 mL of culture medium. Illumination was provided at an irradiance level of 70 µmol m-2 s-1 and CO2-enriched air (2% v/v CO2) was supplied at an aeration rate of 0.400 vvm. Firstly, the microalgal growth kinetics under autotrophic and mixotrophic (using 5 g L-1 glucose + 5 g L-1 galactose as carbon sources) conditions were compared. The results showed that the specific growth rate of the mixotrophic cultivation (MIX=0.019 h-1) of C. vulgaris was 3.5–fold higher than the specific growth rate of cells grown under photoautotrophic condition ( PHO=0.0054 h-1). Under autotrophic growth conditions, biomass productivity (0.004 g L-1 h-1) was lower than that obtained from mixotrophic growth (0.018 g L-1 h-1). The analysis of the composition of Chlorella vulgaris (carbohydrates, proteins, lipids, starch and ash) showed that there were no significant differences between cells that grow in photoautotrophic and mixotrophic regime. The results suggest that mixotrophic growth is a very feasible alternative for the growth of microalgae, since it allows obtaining 4.5–fold higher productivities without affecting the cellular composition.11. session: 2nd International Workshop of Slovak Association for Industrial Biotechnology | PosterPage 1 of 1CONFIS12/01/2015http://www.kirp.chtf.stuba.sk/ssche_conf/index_info.php?idp=258

Evaluation of the effect of mixotrophic growth on Chlorella vulgaris composition

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Universidade do Minho: RepositoriUM

Universidade do Minho: RepositoriUM