Exploring the NMRMetabolic Landscape of Chrysochromulina rotalis: The Impact of PhotobioreactorConfigurations and Culture Conditions

This study utilizes the advanced analytical capabilities of nuclear magnetic resonance metabolomics to perform an untargeted and comprehensive analysis of the metabolic profile ofChrysochromulina rotalis under varying environmental conditions and photobioreactor setups. By identifying key biomolecules, including lipids, pigments, proteins, and carbohydrates, this research highlights the remarkable adaptability ofC. rotalis and its potential as a valuable source of bioactive compounds with industrial application. These findings are supported by experiments conducted at both laboratory and pilot scales. At the laboratory scale, a bubbling bench photobioreactor operated under various LED lights, irradiances, and temperatures. At the pilot scale, 80 L indoor and outdoor tubular and bubble column photobioreactors were used with modified nutrient concentrations and irradiances, along with a 140 L outdoor flat panel photobioreactor. Significant metabolic variations were observed across these setups. Optimal production of carotenoids, chlorophyll <i>c</i>, polyunsaturated fatty acids (PUFA), triacylglycerols (TAG), and 1,2-diacylglycerols occurred at 30 μmol·m^–2·s^–1. Temperature effects revealed that 25 °C favored carotenoids and PUFA, while 35 °C increased glycerol and dimethyl sulfoniopropionate (DMSP). Red light enhanced fatty acids (FA), whereas white light increased osmolytes and docosahexaenoic acid (DHA). Scaling up cultivation further influenced the metabolic profile. Tubular photobioreactors at 268 μmol·m^–2·s^–1 had higher PUFA, TAG, and carotenoid levels, while the indoor bubble columns contained more fucoxanthin, choline, and osmolytes. The outdoor bubble column and flat panel photobioreactors exhibited a similar metabolite composition, with the bubble column showing higher levels of sterols and alanine. Finally, metabolite covariation patterns were explored using Spearman rank correlation, providing insights into metabolic regulation under different conditions. These findings contribute to optimizing photobioreactor-based cultivation strategies for maximizing the production of valuable biomolecules fromC. rotalis.