Nanofiltration for Fermentation-feed Decolorization

Define colour removal alongside product recovery

Fermentation liquor can contain cell fragments, proteins, polysaccharides, colloids, pigments and salts. Decolorization is more than improving visual clarity: the selected route must also preserve the target product and manage viscosity, fouling and downstream purity requirements. Determine whether the product should remain in the retentate or move into the permeate.

Build a staged separation route

Clarification or ceramic/tubular ultrafiltration can remove suspended matter before nanofiltration. The NF stage can then be evaluated for selective retention of colour bodies, desalination or product concentration. Concentration and diafiltration may be followed by resin treatment, crystallization or another finishing step.

The source discusses nanofiltration grades around 80–1,000 Da as a screening range. Molecular weight alone does not identify the best membrane: charge interactions and the composition of the actual broth also influence separation.

Measure performance beyond appearance

Record colour or transmittance using a defined method together with target-product recovery, impurity removal, salt passage and flux. High clarity alone cannot demonstrate an economical process. Test changing concentration and repeated cleaning, and compare representative batches before defining the full-scale arrangement.