Abstract
To produce microalgal biomass, either as a product in its own right or as source of extracted chemical compounds, or to use algae as a means of treating wastewaters, the algae need to be grown in some sort of container or vessel, often called an algal bioreactor.
The diversity of algal bioreactor designs is almost as great as the diversity of the algae that are grown in them, but the reactors can be broadly classified into “open” and “closed” bioreactors. Open bioreactors include the shallow extensive open ponds used to grow Dunaliella salina in Australia, the high-rate oxidation ponds used in wastewater treatment and the widely used raceway ponds of various designs. In closed reactors, the algal culture is fully contained within a vessel, and they are further sub-divided into reactors where the algae are exposed to light (photobioreactors) or dark reactors (fermenters). Culture volume can vary from laboratory scale (culture volume up to ∼500L) to commercial-scale (up to ∼106–109L).