Abstract: A method for preparing a liquid extract rich in phycocyanin from cyanobacteria or microalgae containing phycocyanin in solution, comprising a step of carrying out the cellular lysis of an aqueous suspension of said fresh cyanobacteria or microalgae, a step of macerating the lysate obtained, for several hours in a solution of divalent cations, while releasing the water-soluble molecules in the extracellular space, and one or more steps of clarifying and concentrating the suspension in order to isolate the water-soluble molecules, among them phycocyanin. This method is performed at a pH between 5 and 8.5, at room temperature, without drying.

Abstract: A method for producing membrane polysaccharides from an organism selected from micro-organisms, unicellular organisms and filamentous fungi, the method including at least one step of extracting the membrane polysaccharides as well as a smaller-scale extraction of the soluble proteins, by mechanical treatment of the organism in a ball mill or by physical treatment of the organism by means of ultrasounds.

Abstract: A method for producing membrane polysaccharides from an organism selected from micro-organisms, unicellular organisms and filamentous fungi, the method including at least one step of extracting the membrane polysaccharides as well as a smaller-scale extraction of the soluble proteins, by mechanical treatment of the organism in a ball mill or by physical treatment of the organism by means of ultrasounds.

Abstract: The method for treating a microalgal biomass, characterized in the following steps: having a microalgal biomass comprising at least 15% by weight of lipids relative to the total weight of the biomass and having a dry matter concentration of between 1 g/l and 200 g/l, milling said biomass by a bead mill, operated under the following conditions: the mean diameter of the beads (dGM) ranges from 0.2 to 2.5×10?3 m, preferably from 0.4 to 1.0×10?3 m and is preferably approximately 0.6×10?3 m, the blade-tip agitation speed (?) ranges from 4 to 50 m·s?1, preferably from 5 to 20 m·s?1 and is preferably approximately 8 m·sec?1; recovering the composition obtained.