Supercritical fluid extraction is an environmentally clean technology using carbon dioxide to isolate a variety of natural compounds from microalgae. This benign extraction process provides:
- high selectivities
- short extraction times
- leaves no toxic solvent residues in the extract
Microalgae are microscopic algae found in fresh and marine waters. They are unicellular species that exist as individuals or in groups. Microalgae can range in size from a few micrometers to a few hundred micrometers. They are capable of photosynthesis and produce approximately half of the earth’s atmospheric oxygen and consume carbon dioxide to grow.
Microalgae are extremely diverse organisms and it has been estimated that about 500,000 different species exist that produce over 15,000 novel compounds. Most microalgae produce unique products like carotenoids, antioxidants, fatty acids, peptides, and sterols. These compounds are normally extracted using toxic solvents which can cause compound degradation and leave unhealthy solvent residues in the extract.
Examples of compounds naturally extracted from microalgae using supercritical carbon dioxide.
- Astaxanthin from Haematococcus Pluvialis.
- Alkadienes from Botryococcus braunii
- Carotenoids from Chlorella Vulgaris
- Beta-carotene from Dunaliella salina
- Gamma-linolenic acid (GLA) from Arthrospira maxima (Spirulina)