Euglenoid (flagellate protist) — grouped with microalgae · Freshwater

Euglena

Euglena gracilis

Cell size
15–50 µm
Habitat
Freshwater

Euglena gracilis is a freshwater flagellate microorganism, mixotrophic: it can photosynthesise and, at the same time, feed on organic matter. It has a light-sensitive eyespot (stigma) and a flagellum for movement, and lacks a rigid cell wall (it has a flexible pellicle). It stores energy as paramylon, a β-1,3-glucan unique to this group. It is a model organism and a source of protein, vitamins and paramylon.

Illustrative representation of Euglena (Euglena gracilis) at the cellular level
Illustrative representation of Euglena at the cellular level (characteristic morphology and pigment).

Characteristics

  • Mixotrophic: photosynthesis + heterotrophic nutrition.
  • Eyespot (stigma) and flagellum to swim toward light.
  • Stores paramylon (β-1,3-glucan).
  • No rigid wall: a flexible pellicle that lets it change shape.

Cultivation

It is grown in fresh water in autotrophic, heterotrophic or mixotrophic mode, which gives process flexibility. It tolerates acidic pH, which helps reduce contamination, and reaches high densities in photobioreactors.

Applications

Food supplement (protein, vitamins, paramylon)Nutraceuticals (paramylon β-glucan)Animal feedResearch (model organism)

FAQ

It is a euglenoid, a mixotrophic flagellate protist; it is grouped with microalgae for its photosynthesis and cultivation, although it shares traits with protozoa.

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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