Enclosed non-conventional photobioreactors for microalga production: A review

Recent years have witnessed a growing interest in microalgae, namely toward production of lipids for biodiesel, upgrade of effluents, and synthesis of high added-value compounds. However, industrial production remains a major issue - chiefly due to the constraints posed by classical cultivation systems. Common system designs for microalga cultivation exhibit major bottlenecks, with regard to such specific processing parameters as light, shear stress, gas exchange, and biofouling. Non-conventional photobioreactor arrangements have meanwhile arisen in response to those constraints - yet most of them raise challenges for practical use, despite a number of advantages. A detailed description and discussion of such non-conventional photobioreactor configurations is provided, including a qualitative comparison on their performance - after a brief introduction on parameters that affect photobioreactor performance, and the most common designs suitable for microalga cultivation.