Enhancing the bioactivity of Dunaliella salina extracts through ultra-high pressure supercritical fluid extraction (UHP-SFE)

Dunaliella salina is a green microalga known for its high carotene content, especially in 8-carotene isomers, which are very interesting compounds due to their biological activity. The neuroprotective effect of 8-carotene has been related to the potential prevention of multifactorial neurological pathologies. The use of green extraction processes for the extraction of carotenoids present in D. salina has generated a great advance in the production of carotenoid-enriched extracts. In this work, supercritical fluid extraction at ultra -high pressure (UHP-SFE) at semi -pilot scale has been evaluated for the first time for the extraction of 8-carotene isomers from D. salina. The effect of the pressure was determined by an experimental design, and results showed that both the carotenoid extraction and the neuroprotective activity of the obtained extracts were maximum at 84.9 MPa. At this ultrahigh pressure, the extraction yield was improved 1.35 times, the total terpene and carotene content increased 2.02 and 1.61 times, respectively, and the neuroprotective activity was 2.44 and 1.60 (for acetylcholinesterase and butyrylcholinesterase inhibition capacity, respectively) higher in comparison to the CP-SFE extract. Therefore, UHP-SFE is presented as a more selective extraction process with a higher potential to generate enriched extracts with increased bioactivity than SFE procedures under moderate pressure conditions. Moreover, it has been demonstrated that the use of the semi -pilot UHP-SFE process had a greener potential for the recovery of bioactive carotenoid-enriched extracts than the analytical scale process. Industrial relevance: The industrial scaling-up of extraction processes is a current need. In this sense, in this work, the semi -pilot SFE process has been shown as a more automatic and safer process than the analytical scale. Additionally, the use of UHP in the SFE semi -pilot scale has allowed reducing the extraction time to half of the initial time obtaining higher extraction yields. The UHP-SFE extract provides enriched carotene products with increased neuroprotective activity with greater industrial performance. Therefore, this work becomes the starting point for achieving a high throughput 8-carotene extract process at industrial scale.