A comprehensive approach to optimized ultrasound stimulation for enhanced astaxanthin synthesis in Haematococcus pluvialis: The cultivation strategy

Astaxanthin, a ketocarotenoid, is a potent antioxidant, and the microalga Haematococcus pluvialis is one of the major natural producers of astaxanthin. In this study, a strategy utilizing ultrasound throughout the cultivation process was introduced to induce astaxanthin biosynthesis in H. pluvialis. The effects of various ultrasound intensities, treatment durations, and frequencies on both cell viability and astaxanthin induction were characterized and optimized. The optimized approach was then applied throughout the culture process for each stage, and the physiological effects of long-term ultrasound stimulation on H. pluvialis were analyzed. The results demonstrated a significant increase of 43.2 % in astaxanthin content compared to the control. Ultrasound, as a stress stimulus, not only promoted astaxanthin synthesis but also enhanced its intracellular accumulation by facilitating its distribution throughout the cell. These findings highlight the potential of ultrasound as an effective tool for enhancing astaxanthin production in H. pluvialis, contributing to the sustainable and cost-effective production of high-value antioxidants in the biotechnology industry.