The type and design of photobioreactors for large-scale cultivation of microalgae represent a compromise between the cost of investment and establishment of optimal conditions for obtaining maximum productivity. The cultivation of microalgae can be carried out in various types of bioreactors (Vonshak, 1997). The microalgae Spirulina and Chlorella are the most commonly cultivated in open ponds around the world.

When choosing the appropriate cultivation system, many parameters must be observed:

• Biology of the microalga

• The cost of land, energy, water, and nutrients

• Local climactic conditions

• Final product