An untargeted metabolomic outlook for delineating the reverberations of CO2 exposure to Scenedesmus sp

Abstract

Mitigating CO2 emissions emerges as a crucial focal point within the current environmental and health challenges. In order to evolve to a net-zero future, it is noteworthy that a photosynthetic microalga demonstrates resilience to CO2 stress modulations, thereby efficiently navigating the production of essential bioproducts. RuBisCO, an enzyme responsible for capturing and partitioning CO2 by photosynthetic microalgae, acts differently under varying environmental perturbations, thus affecting its central carbon metabolism. With the target of unraveling the carbon partitioning machinery driven by photosynthetic CO2 for the production of essential bio-commodities such as lipids, tocopherols, phytosterols, etc., along with efficacious CO2 sequestration, an investigation has been carried out for the augmentation of overall growth and bioproduct yield of the Scenedesmus sp. The current work aims to understand the metabolomic and physiological consequences occurring within Scenedesmus sp. under the influence of high CO2 (5 % CO2) and air-CO2 (0.04 %), together with different engineered nutrient media. Our results demystify that under the supplementation of elevated CO2 in Scenedesmus sp., the carbon flux gets diverted towards the accumulation of fatty acids, namely, DHA, EPA, phytosterols, and ?-tocopherol in conjunction with the increase in the biomass content (42 %). Furthermore, the qualitative untargeted metabolomics performed by GC�MS identified nearly 67 metabolites, among which significant fold change has been ascertained for the production of sugars, fatty acids, alcohols, etc., under the impact of 5 % CO2 compared to air-CO2. Eventually, the goal is to comprehend metabolic modulations and photosynthetic carbon partitioning occurring within microalgal cell factories by scrutinizing metabolome regulations for invigorating the path of carbon neutrality. The work focuses on developing a sustainable technology for regulating and mitigating greenhouse gas, i.e., CO2 emissions, on a commercial scale. � 2024 Elsevier B.V.