Design and use of chimeric peptides in a new non-destructive ecological process applied to the extraction of all trans/9-cis β-carotene isomers from Dunaliella salina .

Recently, β-carotene has gained tremendous importance as a bioactive molecule due to the growing awareness of the harmful effects of synthetic products. β-carotene is a high-value natural pigment that has the highest demand in the global carotenoid market owing to its proven antioxidant properties relevant for several diseases. To date, Dunaliella salina is the most important producer of natural β-carotene and is the subject of important industrial efforts. However, the extraction of β-carotene remains challenging since all the proposed techniques present a risk of product contamination or loss of quality due to solvent residuals and low yields. The purpose of this study was to set up a green, ecological, and innovative process of extraction of the two major β-carotene isomers from the halophilic microalgae Dunaliella salina . Based on molecular modeling, docking, and drug design, we conceived and synthesized two chimeric peptides (PP2, PP3) targeting specifically the two major isomers: all-trans or 9-cis β-carotene. The experimental protocol used in this study demonstrated the ability and the efficacy of those two peptides to cross the cell membrane and bind with high affinity to β-carotene isomers and exclude them toward the extracellular medium while preserving the integrity of living cells. Interestingly, the tested peptides (PP2, PP3) exhibit significant β-carotene extraction yields 58% and 34%, respectively, from the total of the β-carotene in microalgae cells. In addition to its simplicity, this process is fast, independent of the source of the β-carotene, and selective. These results would allow us to set up a green, ecological, and very profitable process of extraction from microalgae containing high amounts of β-carotene. Our innovative approach is highly promising for the extraction of Dunaliella salina biomass on an industrial scale.