Porous Substrate Bioreactors: A Paradigm Shift in Microalgal Biotechnology?

Many of the demands in the production of microalgae at a technical scale cannot presently be met by state-of-the-art cultivation technologies based on suspensions. Immobilized cultivation using porous substrate bioreactors (PSBRs) is characterized by a reduction of liquid reaction volumes by several orders of magnitude and has solved several volume-related problems. Recently, PSBRs demonstrated potential for both established and novel applications in microalgal biotechnology, and first insights into biophysical processes have provided an understanding of the benefits of PSBR biofilm cultivation. Further efforts should primarily focus on scale-up and engineering challenges in this emerging field and, additionally, provide experience in the long-term operation of bioreactors. The results may contribute to assessing the technical and economic potential of PSBR cultivation.