Combinatorial Effect of Multiple Abiotic Factors on Up-Regulation of Carotenoids and Lipids in Monoraphidium sp. for Pharmacological and Nutraceutical Applications

Carotenoids have attracted significant interest due to their potential use in human health and nutrition, and their global demand increases by 3.7% annually. Currently, synthetic carotenoids dominate themarket, but possess challenges such as low antioxidant ability, issues with health benefits, and safety concerns. Microalgae are potential producers of natural carotenoids with extraordinary antioxidant properties, although the yield is often low in their natural cycle. The present investigation aimed to analyze the effect ofmultiple abiotic factors on enhancing algal carotenoids synthesis and othermetabolites without affecting growth. The potential microalgaeMonoraphidium sp. were grown under altered nutrient and light conditions employing RSM-CCD. The optimized conditions, such as Nitrogen (5 g center dot L-1), Phosphorus +Potassium (250 mg center dot L-1), Sulphur (70 mg center dot L-1), and light (137.5 mu mol center dot m (2)center dot S-1), resulted in increased biomass (1357.36 mg center dot L-1), lipid accumulation (40.28% of dry biomass), and carotenoids (16.26 mu g center dot mL(1)) as compared to the control conditions. The total carotenoids fraction consisted of astaxanthin (14.8%), violaxanthin (3.61%), lutein, (45.12%), 9-cis- beta carotene (7.62%), and beta-carotene-5,6-epoxide (24.21%). Among them, violaxanthin (1.32-fold), astaxanthin (1.19-fold), 9-cis-beta carotene (1.07-fold), and beta-carotene-5,6-epoxide (1.08-fold) content increased while lutein (1.32-fold) content decreased significantly. The improvement in algal carotenoids under novel culture conditions provides a significant advantage to pharmaceutical and nutraceutical industries.