Cyanobacterium (prokaryote) — grouped with microalgae · Alkaline freshwater

Spirulina

Arthrospira platensis / A. maxima

Cell size
Tricomas filamentosos en espiral
Habitat
Alkaline freshwater

Spirulina (genus Arthrospira) is, strictly speaking, a filamentous prokaryotic cyanobacterium, although it is usually grouped with microalgae due to its use and cultivation. It forms spiral trichomes and grows in alkaline, high-pH fresh waters. It is one of the most FAO-documented microalgae-based foods, with a very high protein content.

Illustrative representation of Spirulina (Arthrospira platensis / A. maxima) at the cellular level
Illustrative representation of Spirulina at the cellular level (characteristic morphology and pigment).

Characteristics

  • Spiral-shaped filaments (trichomes), visible under the microscope.
  • Very high protein content (≈ 60–70 % of dry weight, per FAO and literature).
  • Rich in phycocyanin (blue pigment), iron and B-group vitamins.
  • Grows in alkaline (high-pH) waters, which reduces contamination.

Cultivation

It is produced mainly in open raceway ponds in alkaline (bicarbonate) fresh water, using its high pH as a natural barrier against contaminants. It is also grown in photobioreactors for greater control.

Applications

Human food supplement (protein, phycocyanin)Animal feed and aquacultureNatural colorant (phycocyanin)Cosmetics and nutraceuticals

FAQ

Technically it is a cyanobacterium (prokaryote), but it is grouped with microalgae due to its cultivation and food use.

It is the signature blue pigment of Spirulina, valued as a natural colorant and antioxidant.

Sources

  1. Richmond, A. & Hu, Q. (eds.) (2013). Handbook of Microalgal Culture: Applied Phycology and Biotechnology. Wiley-Blackwell.
  2. Chisti, Y. (2007). Biodiesel from microalgae. Biotechnology Advances, 25(3), 294–306.
  3. Spolaore, P. et al. (2006). Commercial applications of microalgae. Journal of Bioscience and Bioengineering, 101(2), 87–96.
  4. Mata, T.M. et al. (2010). Microalgae for biodiesel production and other applications: A review. Renewable and Sustainable Energy Reviews, 14(1), 217–232.

Scientific outreach based on specialised literature. Scientific review: pending.

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