Mixotrophic cultivation of Galdieria sulphuraria for C-phycocyanin and protein production

Fabian Abiusi, Pedro Moñino Fernández*, Stefano Canziani, Marcel Janssen, René H. Wijffels, Maria Barbosa

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

2 Citations (Scopus)

Abstract

G. sulphuraria is a polyextremophilic microalga that can tolerate low pH, high temperature and high osmotic pressure. We cultivated G. sulphuraria ACUF 064 in chemostat at a biomass concentration of 134 to 243 g·m−2 aiming for maximal pigment content without compromising biomass productivity. Autotrophy was compared to ‘oxygen balanced’ mixotrophy with intracellular recirculation of oxygen and carbon dioxide. No differences were found in C-phycocyanin (C-PC) and protein content between autotrophic and mixotrophic cultures. In mixotrophy the biomass productivity and concentration were doubled compared to the photoautotrophic counterpart. In mixotrophy aeration was not needed and 89% of the substrate carbon was converted into biomass. Mixotrophically grown biomass contained 10% w/w C-PC which, combined with its high areal biomass productivity (49 g·m−2·day−1), sums up as one of the highest C-PC areal productivities ever reported (5 g·m−2·day−1) under 24 h/24 h illumination. C-PC extracted from G. sulphuraria was more stable than the currently used C-PC extracts from Spirulina. No significant loss of color was observed down to a pH of 3 and up to a temperature of 55 °C. G. sulphuraria had a protein content of 62% w/w and compared favorably with FAO dietary recommendation of adults regarding amino acid composition. G. sulphuraria contains a high proportion of essential, sulfur amino acids compared to Chlorella, Spirulina and soybean protein. Due to its attractive amino acid profile and high protein content, G. sulphuraria is a good candidate for food and feed applications to overcome sulfur amino acid deficiencies. In addition, oxygen balanced mixotrophy allows for efficient and productive cultivation of G. sulphuraria biomass.

Original languageEnglish
Article number102603
JournalAlgal Research
Volume61
DOIs
Publication statusPublished - Jan 2022

Keywords

  • Acid stable phycocyanin
  • Amino acid profile
  • Oxygen balance
  • Phycocyanin productivity
  • Protein production
  • Thermo stable phycocyanin

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