Characterization and optimization of a fermentation process for the production of high cell densities and lipids using heterotrophic cultivation of chlorella protothecoides

Ghidossi, Tracy (Dublin City University, Dublin, Ireland) ; Marison, Ian (School of Engineering and Architecture (HEIA-FR), HES-SO // University of Applied Sciences Western Switzerland) ; Devery, Rosaleen (Dublin City University, Dublin, Ireland) ; Gaffney, Darragh (Monahan Bioscience Ltd., Monaghan, Ireland) ; Forde, Ciaran (Monahan Bioscience Ltd., Monaghan, Ireland)

This article reports an in-depth characterization and optimization of a fermentation process with the aim of increasing the production of high cell densities as a prerequisite for high productivity of lipids. The freshwater microalgae Chlorella protothecoides was grown heterotrophically in a bioreactor on aerated and stirred cultivation medium with glucose as a carbon source and yeast extract as a nitrogen source. The detailed effect of carbon to nitrogen (C/N) ratio on growth and lipid content of C. protothecoides was studied. Results show that with a C/N ratio lower than 12, the medium was carbon-limited, favoring cell proliferation, and under nitrogen-starvation conditions, (higher C/N ratios), lipid accumulation was enhanced. A two-stage, fed-batch process was developed and achieved a maximum of 255.3 g/L of biomass over 228 h of fermentation, from a low initial cell density (< 2 g/L). The specific growth rate, measured when C/N ratio was low, was 0.078 h−1.The lipid productivity was 16.7 g/L/day, and the maximum lipid content was 58 % (w/w) of the dry cell weight. This is the first time that such a very high cell density and lipid productivity have been achieved. The results offer potential for the production of important algae-derived commercial products.


Keywords:
Article Type:
scientifique
Faculty:
Ingénierie et Architecture
School:
HEIA-FR
Institute:
ChemTech - Institut des technologies chimiques
Date:
2017-10
Pagination:
7 p.
Published in:
Industrial Biotechnology
Numeration (vol. no.):
2017, vol. 13, no. 5, pp. 253-259
DOI:
ISSN:
1550-9087
Appears in Collection:

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 Record created 2021-05-07, last modified 2021-05-28

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