4. Extraction of compounds of interest from spirulina

The compounds of interest are generally found in the microalgae cell and therefore need to be separated from the biomass. For this, it is necessary to disintegrate the cells to facilitate diffusion of their contents into the disintegration medium. This is followed by an extraction step. For a given intracellular compound, the ideal cell wall embrittlement treatment is one that selectively releases the targeted compound using the least amount of energy possible. The choice of cell wall disintegration method depends on the cell wall structure of the micro-algae species, the location of the compound, its size, solubility and the energy applied. Depending on the level of cell disintegration, techniques can be classified as :

• physical (drying, ultrasound, pulsed electric fields and microwaves),

• mechanical (ball...