Adaptive evolution of Schizochytrium sp. under light and H₂O₂ condition to regulate its fatty acid and terpene biosynthesis

Schizochytrium sp. is an important marine microalga rich in polyunsaturated fatty acids. As an oleaginous marine microorganism, Schizochytrium sp. can accumulate different high-value-added lipid chemicals such as squalene and carotenoids. In this paper, adaptive evolution technology based on light and H₂O₂ stress was proposed to improve the cell adaptability and terpene biosynthesis. Two adaptive strains of ALE10 and ALE20 were obtained with high terpenoid biosynthesis ability. Coupled with stress regulation fermentation, the EPA percentage in total fatty acids of the adaptive strain reached 11 %, which was increased by 5-fold. Meanwhile, the squalene content also reached a maximum of 102.2 mg/L and the content of β-carotene increased by 53.75 %. This study may provide a new adaptive method for the efficient biosynthesis of lipid-soluble secondary metabolites.