Microalgae for Biofuels and Animal Feeds

TLDR

Microalgae are mainly cultivated on a small scale for high‑value nutritional products, but to become viable for low‑cost commodities they must be produced at much lower cost and with high‑productivity strains suitable for large open‑pond cultivation. The review examines how microalgae biomass can be produced cost‑effectively for low‑cost commodities such as biofuels and animal feeds using sunlight and CO₂. The authors survey diverse cultivation systems, algal species, harvesting techniques, and biomass processing technologies being developed worldwide to meet these commodity requirements. Only raceway‑type open pond systems are deemed suitable for low‑cost commodity production.

Abstract

The potential of microalgae biomass production for low-cost commodities—biofuels and animal feeds—using sunlight and CO2 is reviewed. Microalgae are currently cultivated in relatively small-scale systems, mainly for high value human nutritional products. For commodities, production costs must be decreased by an order of magnitude, and high productivity algal strains must be developed that can be stably cultivated in large open ponds and harvested by low-cost processes. For animal feeds, the algal biomass must be high in digestible protein and long-chain omega-3 fatty acids that can substitute for fish meal and fish oils. Biofuels will require a high content of vegetable oils (preferably triglycerides), hydrocarbons or fermentable carbohydrates. Many different cultivation systems, algal species, harvesting methods, and biomass processing technologies are being developed worldwide. However, only raceway-type open pond systems are suitable for the production of low-cost commodities.