Sodium oleate potentiates the concurrent overproduction of lipids and carotenoids in Chlorella vulgaris towards biofuel and nutraceutical applications

Abstract

Microalgal metabolites have emerged as potential commodity components due to their notable beneficial nutritional and economic properties, and thus, their overproduction is of paramount importance to combat the existing ecological and dietary issues. However, the production titer of these metabolites by the algal systems at optimal cultivation conditions is inadequate to meet the burgeoning global demand for those metabolites. Therefore, a pressing demand remains to concurrently co-produce valuable metabolites without compromising cellular biomass production. Here, we report an effective strategy that simultaneously overproduces lipids, biomass and carotenoids in Chlorella vulgaris by providing sodium oleate (NaOL) in the cultivation medium. Supplement of sodium oleate at the optimal concentration (50 µg/mL) at increased light intensity enhances cellular growth rate in a dose-dependent manner. Total lipid content was quantified, which showed that lipid content was significantly increased in the NaOL-treated cells by 2.08-fold than that of the control cells. Interestingly, spectrophotometric determination of total carotenoids showed that carotenoid content was increased by 2.48-fold in the T5 (50 µg/mL) NaOL treated cells compared to the control. Interestingly antioxidant analysis showed that NaOL provision alleviated the antioxidant potential of the algal cells. Together, this report exemplifies the potential strategy to preclude the existing intricacies of co-producing metabolites in C. vulgaris by supplementing NaOL, thereby highlighting the viable chemical engineering approach for the biological production of commercially essential metabolites in microalgae.