Industry · 21 April 2026
Sunlight or sugar? Two very different ways to grow microalgae, each with its own economics, products and footprint.
Most people picture algae growing in sunlight — and phototrophic cultivation in ponds and photobioreactors is still the most common route. It uses light and CO₂, which makes it attractive for carbon capture and low-input production.
Heterotrophic cultivation grows suitable strains in the dark on organic carbon such as sugars, in fermenters similar to those used for yeast. Densities can be far higher and conditions tightly controlled.
The trade-off: phototrophic systems are limited by light delivery, while heterotrophic systems depend on feedstock cost and lose the photosynthetic pigments some markets value.
Increasingly, the answer is both. Mixotrophic strategies and sequential processes combine the strengths of each to hit the right product, price and sustainability profile.