Effects of Audible Sound and Ultrasound on Microalgae: Growth Responses and Metabolite Production

Developing sustainable strategies to enhance microalgal productivity is a major challenge in modern biotechnology. Beyond optimizing light, nutrient supply, and temperature, physical stimulation methods have recently attracted growing interest. Among these, audible sound and ultrasound have emerged as promising tools capable of influencing growth, biomass accumulation, and metabolite production in several microalgal species. Although the available literature is still limited, current evidence suggests that acoustic stimulation can alter cellular physiology through mechanosensitive responses, changes in membrane permeability, and modulation of metabolic activity. This review summarizes current knowledge on the effects of sound waves on microalgae, discusses potential mechanisms involved in acoustic perception, and highlights future research directions.