Polyphenol regulates metabolic and physiological properties of microalgae to accumulate biocompounds

Abstract Background The development of affordable strategy to concurrently enhance microalgal biomass and biocomponents is warranted for commercial applications. Here, we investigated the efficacy of a cheap and natural polyphenol, tannic acid, on regulating metabolic and physiological properties of oleaginous microalga Phaeodactylum tricornutum to overproduce biocompounds. Result Tannic acid provision regulated the key metabolic pathways to enhance algal biomass and lipids in a dose-dependent manner without direct impact on photosynthesis. It reduced oxidative stress and reallocated carbon precursors towards lipogenesis. Lipidomic analyses showed that tannic acid provision unprecedentedly regulated the key lipogenic pathways, enhanced glyco- and neutral-lipids by 1.29- and 1.54-fold, respectively, whereas phospholipids were significantly altered. Tannic acid facilitated polyunsaturated fatty acid overproduction with a specific increment of EPA and DHA by 1.18- and 2.25-fold, respectively. Transcriptomic analysis demonstrated that tannic acid upregulated the expression of multiple genes involved in lipogenesis. Conclusion Here, we dissected the potential of tannic acid, a natural and cheaper polyphenol, on concurrently enhancing lipids and PUFAs without impairing physiological properties in P. tricornutum. The findings provide novel insights into the mechanistic roles of polyphenol as a potential chemical modulator.