Electrical Stimulation for Microalgal Growth and High-Value Bioproduct Production: Mechanistic Insights and Emerging Opportunities

The increasing severity of climate change and global energy insecurity has intensified the demand for sustainable and carbon-neutral biofuel production technologies. Microalgae are considered promising bioresources due to their rapid growth, high photosynthetic efficiency, and exceptional CO2 fixation capability. However, large-scale commercialization remains limited by the metabolic trade-off between biomass growth and metabolite accumulation. Electrical stimulation (ES) has gained wide attention as an emerging strategy for regulating microalgal metabolism through modulation of membrane permeability, electron transport, intracellular redox balance, and reactive oxygen species (ROS)-mediated signaling pathways. This narrative review systematically summarizes recent advances in ES-assisted microalgal systems, focusing on biomass enhancement, lipid accumulation, and astaxanthin biosynthesis. Particular attention is given to the mechanisms by which electrical inputs affect photosynthetic activity, calcium-mediated signaling, intracellular carbon partitioning, and stress-responsive metabolic mechanisms. Overall, ES offers a versatile and environmentally friendly platform to stimulate microalgal growth and metabolite accumulation, supporting the advancement of sustainable microalgae-based biorefineries.