Method for obtaining an aqueous extract of dunaliella salina and cosmetic uses of same

A method for obtaining an aqueous extract of a Dunaliella salina microalgae, wherein said microalgae is cultured in the absence of light in a culture medium comprising a yeast extract, sugar and salt, the method comprising:

• a) solubilising a yeast extract in water;
• b) adding glucose to the mixture obtained in a);
• c) adding Dead Sea salt;
• d) after total solubilisation of the salt in the mixture obtained in b), the culture medium thus obtained has a pH of between 5 and 8, and the microalgae Dunaliella salina is added thereto;
• e) moderately stirring the mixture obtained in d), in darkness and at room temperature, for a period of at least 12 hours, in order to allow the fermentation of the microalgae Dunaliella salina;
• f) grinding and then filtering the fermented Dunaliella salina mixture obtained in e) in order to separate the soluble and insoluble materials;
• g) recovering a soluble aqueous raw extract to which Dead Sea salt or a preservative such as sodium benzoate is added;
• h) carrying out sterilising filtration with a porosity threshold of less than or equal to 0.2 μm;
• and
• i) obtaining a fermented aqueous extract of Dunaliella salina in which the pH is between 3.5 and 4.5.