Microalgal Biotechnology: Pigments, Lipids, Proteins and Beyond

Microalgae are photosynthetic chemists. Across their lineages they make carotenoids, long-chain fatty acids, and pigments with no land-plant equivalent. Microalgal biotechnology is the practice of growing the right species under conditions that make it produce the compound you want — then extracting that compound economically. Here is the map of what works, what is promising, and what oversold itself.

Pigments: the crown jewels

Astaxanthin from Haematococcus pluvialis — the red ketocarotenoid farmed for salmon pigmentation and the nutraceutical market, produced by stressing green cyst cells into red ones. Beta-carotene from Dunaliella salina — grown in hypersaline ponds where few competitors survive. Phycocyanin from Arthrospira — the blue pigment behind 'spirulina blue' food colouring. Fucoxanthin from diatoms such as Phaeodactylum — researched for metabolic applications, still mostly at lab scale.

Lipids and proteins

Marine microalgae are the base of the omega-3 supply chain for aquaculture: Nannochloropsis for EPA, Isochrysis and Pavlova for DHA-rich hatchery feeds. Human-market omega-3 from microalgae is a real, growing category — it is where the DHA in infant formula comes from. On the protein side, Arthrospira and Chlorella are established whole foods with protein contents among the highest of any cultivated organism; both have their own species guides.

The honest boundaries

Three caveats keep this field honest. First, strain matters more than species: compound content varies enormously between strains of the same species, so published percentages are ranges, not properties. Second, production requires stress: many high-value compounds are stress responses, which trades growth rate against content — a genuine engineering tension. Third, economics filter everything: plenty of compounds are biologically real and commercially impossible at current costs. The established products above are established precisely because biology and economics agreed.