Spectral Changes by Dye Sensitized Solar Modules Influence the Pigment Composition and Productivity of Arthrospira maxima and Increase the Overall Energy Efficiency

The integration of semi-transparent photovoltaics (PVs) with photobioreactors (PBRs) is a promising strategy to increase photoconversion efficiency, ensuring simultaneous electricity and algal biomass production. In this study, Arthrospira maxima is cultivated in an integrated system with a dye-sensitized solar module (DSSM) to the front of the PBR to assess the possible advantages for biomass and phycocyanin production. The application of the DSSM does not influence biomass production, with the remarkable advantage of producing additional electric energy. However, an acclimation of pigment is observed, as DSSM causes a change in the transmitted light spectrum. Further experiments are conducted to investigate the effect of light quality using monochromatic light-emitting diodes (LEDs) as controls. Phycocyanin-targeted wavelengths exhibit a major impact on biomass growth and pigment productivity: low intensity enhanced process efficiency, suggesting that low light is preferable to enhance culture performance with respect to white light. The application of third-generation PVs is only potentially advantageous if the transmission spectra of the module color and its aperture area are carefully designed. The application of monochromatic LEDs on PBRs also highlights the importance of properly managing the operative conditions to avoid energy losses.