Sustainable phycocyanin production from Arthrospira platensis using solar-control thin film coated photobioreactor

Abstract

Solar irradiance consists of photosynthetically-active photons that can be transformed to valuable biomolecules by microalgae. Light also has undesirable non-photosynthetic photons, such as ultraviolet and infrared wavelengths that heat up algal closed photobioreactors above optimum temperatures for growth. In this study, a solar control infrared blocking film (IRF) is applied to an algal flat plate photobioreactor to block excessive non-photosynthetic photons and regulate the temperature profile of Arthrospira platensis cultures for the production of C-phycocyanin (C-PC). The performance of the IRF is compared against other cooling mechanisms such as insulated-glazed photovoltaic (IGP), conventional water-jacket (CWJ) and a no heat control (NHC) photobioreactors. Experimental results show that the maximum temperature (30.94 ± 0.09 °C) in the IRF culture is only 5% higher than that in CWJ culture but 33% lower than that in NHC cultures. No significant differences were found in C-PC content or biomass productivity when Arthrospira is grown using IGP, CWJ or IRF but is significantly lower in NHC photobioreactors. Chlorophyll a fluorescence probing of A. platensis shows that IRF, IGP and CWJ cultures are not thermally stressed, however, NHCs cultures are highly stressed due to supraoptimal temperatures. Our results clearly indicate that solar control film is a potential tool for blocking non-photosynthetic photons and managing culture temperature in flat plate photobioreactors for sustainable C-phycocyanin production from A. platensis.