Optimization of Culture Conditions for High Cell Productivity and Astaxanthin Accumulation in Vietnam's Green Microalgae HB and a Neuroprotective Activity of Its Astaxanthin.

BACKGROUND

, a green microalga, is a rich source of natural astaxanthin and a potent antioxidant with high commercial value. This study investigates the biological characteristics and potential of HB isolated from Hoa Binh, Vietnam, for growth and astaxanthin accumulation using a two-phase culture method.

METHODS

HB was cultured in a C/RM medium at 25 °C, and morphological characteristics were examined. NMR spectroscopy was used to determine the structure of the astaxanthin, which was extracted using the Soxhlet method.

RESULTS

After 22 days, the highest cell density (4.96 × 10 cells mL) was achieved under optimized light and ultraviolet conditions. Nutrient deprivation followed by bicarbonate supplementation resulted in a maximal astaxanthin accumulation of 48.8 mg g dry cell weight within two days. The extracted astaxanthin demonstrated potent antioxidant activity (IC: 3.74 mg mL) compared to ascorbic acid (IC: 18.53 µg mL) and exhibited strong acetylcholinesterase inhibition (IC: 297.99 µg mL). It also showed neuroprotective effects against HO and amyloid beta-induced neurotoxicity in C6 cells.

CONCLUSIONS

This study highlights HB as a promising source for large-scale astaxanthin production with potential applications in neuroprotective health products.