Encapsulation of Photosystem I in organic microparticles increases its photochemical activity and stability for ex vivo photocatalysis

Photosystem I (PSI) is a pigment binding multi-subunit protein complex involved in the light phase of photosynthesis, catalyzing a light dependent electron transfer reaction from plastocyanin to ferredoxin. PSI is characterized by a photochemical efficiency close to one, suggesting its possible application in light dependent redox reaction in extra-cellular context. The stability of PSI complexes isolated from plant cells is however limited if not embedded in a protective environment. Here we show an innovative solution for exploiting the photochemical properties of PSI, by encapsulation of isolated PSI complexes in PLGA (poly lactic-co-glycolic acid) organic microparticles. These encapsulated PSI complexes were able to catalyze light dependent redox reactions with electron acceptors and donors outside the PLGA microparticles. Moreover, PSI complexes encapsulated in PLGA microparticles were characterized by a higher photochemical activity and stability compared to PSI complexes in detergent solution, suggesting their possible application for ex vivo photocatalysis