The invention relates to a method and device for the continuous production of endogenous or recombinant native polypeptides. The method and device comprise the steps of cultivating recombinant microorganisms in a bioreactor, withdraw a sample of the microbial suspension in the reactor in a continuous manner and subject the same to a first filtration to separate the biomolecules from the microbial suspension and to a second filtration to separate the biomolecules of interest form the other biomolecules.