The application of ultrafiltration for separation of glycerol solution fermented by bacteria

A biotechnological synthesis generated a fermentation broth containing the dissociated forms of organic compounds and residual mineral salts. An effective method of selective removal of the ionic species and organic compounds from solutions comprises nanofiltration and reverse osmosis. Ultrafiltration (UF) was used in this work as a pre-treatment method for the preparation of feed for these processes. The UF study was carried out with a real broth, which was obtained using Citrobacter freundii bacteria for the fermentation of glycerol solutions, resulting in the UF permeate with turbidity below 0.1 NTU. However, a significant decline of the permeate flux was observed during the UF process. The influence of the transmembrane pressure on the fouling intensity of used ceramic membranes was investigated. A periodical membrane cleaning was carried out by rinsing with water and a 1 wt % solution of sodium hydroxide. The applied cleaning procedures permitted to restore the initial permeate flux.