Method for separating biomolecules

A method for separating a biomolecule from a fluid, wherein the biomolecule is produced by biological cells in a perfusion bioreactor provided as part of a bioprocessing system not having a surge tank after the bioreactor, the method comprising:

• 110. forwarding a product fluid comprising the biomolecule and biological cells from the perfusion bioreactor during a bioreactor product output time period, tBRp, which constitutes a first part of a bioreactor cycle time period, tBR;
• 210. loading a first separation device with the product fluid obtained in step 110 during a first separation loading time period, tS1l, which constitutes a first part of a first separation cycle time period tS1;
• 130. pausing the forwarding of the product fluid from the perfusion bioreactor during a bioreactor non-product output time period, tBRn, which constitutes a second part of the bioreactor cycle time period;
• and
• 220. pausing the loading of the first separation device during a second part of the first separation cycle time period, said second part comprising:
• optionally a first separation wash time period, tS1w,
• a first separation product elution time period, tS1p, and
• a first separation regeneration time period, tS1r;
• wherein
• tBR=tBRp+tBRn,
• tS1>=tS1l+tS1w+tS1p+tS1r,
• and
• tBRn>=tS1w+tS1p+tS1r;
• repeating steps 110, 210, 130, and 220 n times, wherein n is the number of times required to complete a production run.