Continuous single pass diafiltration with alternating permeate flow direction for high efficiency buffer exchange
Tan, R. / Hezel, F. / Franzreb, M. (2020)
Journal of Membrane Science, 2021, 619, 118695
- Date: September 2020
Looking at current trends within downstream processing (DSP) of high value bioproducts, it shows that there are ongoing efforts in replacing batch processes by continuous variants. However, a unit procedure which still lacks a simple and compact continuous variant is diafiltration. Here, we present such a single piece of diafiltration equipment achieving continuous buffer exchange of up to 99.90%. The device is composed of a 3D-printed single pass diafiltration (SPDF) module containing two commercial ultrafiltration membranes. While the retentate is flowing through a narrow channel between the two membranes, the channels above and below can supply diafiltration buffer or remove permeate solution. The obtained results illustrate systematically the vulnerability of the device to the effect of concentration polarization at the membrane surface, and that this problem can be strongly reduced using an alternating direction of diafiltration buffer perfusion through the membranes as process inherent backflush. By this, a quasi-stationary operation could be obtained during continuous diafiltration, making the device an interesting option for in-process buffer exchange.