Microalgae are a diverse group of tiny photosynthetic organisms that grow in water. Unlike seaweed (macroalgae), individual microalgae are invisible to the naked eye, though large cultures appear as dense green, red, or golden liquids. Common species used in food production include Chlorella, Spirulina (technically a cyanobacterium), and Schizochytrium.
Different species are cultivated for different purposes. Some are grown for their high oil content, particularly DHA omega-3 fatty acids, providing a plant-based alternative to fish oil. Others are valued for pigments like astaxanthin, or as whole-cell nutritional supplements. Microalgae-derived DHA is increasingly used in infant formula, food fortification, and vegan supplements.
Microalgae farming is one of the more resource-efficient forms of food production. The organisms grow rapidly, can be cultivated on non-arable land, and convert sunlight and carbon dioxide into useful compounds with relatively little waste.
How it's produced
Microalgae are farmed in controlled aquaculture systems. Open-pond systems use large, shallow raceways where algae grow in sunlight and are kept circulating with paddle wheels. Closed photobioreactor systems use sealed tubes or panels that offer greater control over contamination, light exposure, and temperature.
Once the culture reaches target density, the algae are harvested by centrifugation or filtration — a destructive process, as the cells are collected whole. The biomass is then dried, or processed further to extract oils, pigments, or other compounds. Most commercial microalgae production occurs in purpose-built facilities in warm climates, though indoor systems with artificial lighting are becoming more common.
What it costs the planet (per kilo)
≈ Estimated from its category — typical for vegetable oils, not measured for this item yet. Sources & methods →
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