Process for freeze drying of a sample of fecal microbiota

The present invention relates to a process of lyophilizing a sample of fecal microbiota from a donor subject, comprising the steps of: A) mixing a sample of fecal microbiota from a donor subject with a diluent selected from polyols, di- to pentasaccharides, maltodextrins and mixtures thereof, and B) freezing the mixture obtained in a) at a temperature below -50 ° C, preferably between -70 ° C and -100 ° C, then lyophilization.