Valorization of Phaeodactylum tricornutum for integrated preparation of diadinoxanthin and fucoxanthin.

Integrated preparation of high-purity carotenoids from marine microalgae using green and efficient methods still faces enormous challenges. In this study, valorization of the economic Phaeodactylum tricornutum using integrated preparation of diadinoxanthin (Ddx) and fucoxanthin (Fx) was explored containing four steps including algae cultivation, solvent extraction, ODS open-column chromatography, and ethanol precipitation for the first time. Several essential key factors were optimized for simultaneously extracting Ddx and Fx from P. tricornutum. ODS open-column chromatography was used to isolate Ddx and Fx. Purification of Ddx and Fx was accomplished using ethanol precipitation. After optimization, the purity of Ddx and Fx was more than 95%, and the total recovery rates of Ddx and Fx were approximately 55% and 85%, respectively. The purified Ddx and Fx were identified as all-trans-diadinoxanthin and all-trans-fucoxanthin, respectively. The antioxidant capacity of the purified Ddx and Fx was assessed using two tests in vitro: DPPH and ABTS radical assays.