Separation of cells and proteins from fermentation broth using ultrafiltration

Ultrafiltration of fermented cheese whey broth was studied using a lab scale cross-flow membrane system. The molecular weight cut-offs (MWCO) of the used membranes were 5000 Da and 20,000 Da. The experiments were conducted at five levels of transmembrane pressure (70, 140, 210, 280, and 420 kPa), two temperatures (21 and 37 °C) and two cross-flow velocities (1 m/s and 2 m/s). The permeate flow-rate decreased with time due to fouling of the membrane. Higher transmembrane pressure and cross- flow velocity caused higher permeate flux. Transmembrane pressure and cross-flow velocity had no significant effect (P > 0.1) on protein retention ratio. Higher MWCO of the membrane caused higher permeate flux and reduced the crude protein retention ratio. However, the MWCO of membrane had no significant effect on the protein retention ratio.