Enhanced Photosynthesis of Carotenoids in Microalgae Driven by Light-Harvesting Gold Nanoparticles

The synthesis of high-value bioproducts has attracted immense attention in the scientific and industrial fields due to its health and economic benefits. Such bioactive compounds are typically manufactured by either synthetic approaches from petrochemical sources or biogenetic pathways existing in living organisms. Herein, we report a hybrid bioinorganic light-driven cell factory by integrating microalgae Chlorella zofingiensis with efficient light-harvesting gold nanoparticles (AuNPs) and demonstrate the enhanced photosynthesis of natural bioproducts (i.e., carotenoids) for the first time. Our results show that smaller AuNPs (5 nm) can be internalized by C. zofingiensis and increase the production of carotenoids to 10.7 ± 1.2 mg/L, 42.7% higher than the native microalgae. We confirm that AuNPs can significantly improve the relative electron transport rate in photosystem II and reactive oxygen species (ROS) levels in microalgae, thus elevating the overall photosynthesis toward carotenoids. This rationally designed biohybrid system provides a promising alternative to produce high-value bioproducts of interest.