Illuminated aerosol-based PhotoBioReactor for cultivation of phototrophic Biofilms

Terrestrial cyanobacteria are living embedded in extracellular polymeric substances (EPS) and show a pronounced surface associated growth. Due to their ability of CO₂ fixation using a special CO₂ concentration mechanism, they are good candidates for an extension of the CO₂ circle. CO₂ could be bound and simultaneously, dietary supplements, animal feed, natural dyes, fertilizer, and antimicrobials could be produced. An aerosol‐based PhotoBioReactor (PBR) was developed for cultivation at the Technical University of Kaiserslautern. It imitates the natural habitat of terrestrial cyanobacteria leading to higher growth rates in comparison to submerged cultivations. Through targeted drought stress and different surfaces the EPS production can be enhanced. Besides chlorophyll a and carotenoids, cyanobacteria developed additional light‐harvesting complexes, so‐called phycobilisomes, consisting of different chromophorylated phycobiliproteins. Some cyanobacteria have the ability of “complementary chromatic adaptation” and therefore can change the pigment composition depending on the available light spectrum and quality. The blue pigment C‐phycocyanin is a promising product since consumers prefer natural coloring agents produced under ecological conditions and whose production can be increased by changing light composition. Aerosol‐based PBRs are lighter than submerse PBRs and could be implemented on facades to expand agriculture areas.