Comprehensive Effects of Flashing/Pulsed Light on Microalgae: Molecular Mechanisms and Biotechnological Applications

ABSTRACT: Microalgae serve as a cell factory for sustainable biomass and high-value compound production, yet their industrial-scale cultivation is often constrained by light energy utilization. The continuous illumination often limits photosynthetic efficiency and biomass and high-value compound productivity due to a kinetic mismatch between rapid photochemical reactions (picosecond-to-millisecond scale) and slower downstream biochemical processes (like Calvin-Benson cycle). Flashing/pulsed light strategies mitigate these by delivering intermittent photons, exploiting the biological effects to enhance quantum yield, biomass productivity, and targeted metabolites accumulation. This mini review emphasizes historical development of core concepts, molecular mechanisms, Photosystem II (PSII) dynamics, plastoquinone buffering, temporal decoupling, parameter optimization, the applications in autotrophic and mixotrophic modes, and photobioreactor innovations. An updated timeline to date highlights the emerging AI-driven adaptive lighting systems that promise real-time optimization of flashing regimes. This review summarizes current understanding, critical knowledge gaps and future directions, particularly in intelligent control for scalable, energy-efficient cultivation of microalgae by the rational design of advanced photobioreactors and cultivation strategies.