Abstract

Beta-carotene is known as one of nature’s most powerful antioxidants. It is also a major pro-vitamin A nutrient, and simulative effects on the immune system. Nowadays, the microalga Dunaliella is the best commercial source of natural β-carotene since it has a mixture composed mainly of 9-cis isomer which is evident is a better antioxidant than the all-trans isomer. In addition, synthetic β-carotene only contains the all-trans isomer, natural (all-trans) beta-carotene is found together with other carotenoids. In this study, we chose the microalga Dunaliella sp. which is isolated at salter in Vietnam since it could grow more easily in this climate. Therefore, it has a great potential for large-scale culture in Vietnam coast. The research aims at investigating the optimization of cultural conditions and stresses depth for cell growth and β-carotene production of this alga. The obtained results showed that the highest cell density was attained at 2M salt concentration with 2.7 ×106 cell/ml and productivity of dry biomass was 0.321g/l. Furthermore, β-carotene content increased to 9% of dry biomass under high salinities (NaCl 3M) or nitrogen starvation of cultural condition.