The invention relates to a method for fractionating the components of a biomass of protein-rich microalgae of the genus Chlorella, characterized in that it comprises the following steps:providing a microalgal biomass produced by fermentation,optionally, washing the biomass so as to eliminate the interstitial soluble compounds,thermal permeabilization of the biomass at a temperature of between 50 and 150° C., preferably 100 and 150° C., for a duration of between 10 seconds and 5 minutes, preferably for a duration of between 5 seconds and 1 minute,separation between the biomass thus permeabilized and the soluble fraction by a centrifugation technique, more particularly multistage centrifugation,optionally, recovery and clarification of the soluble fraction obtained in this way by microfiltration so as to remove residual insoluble substances therefrom,separation of the preceding soluble fraction by precipitation, so as to obtain a peptide isolate and a peptide concentrate.
