Inorganic Carbosep membranes with separation layer of zirconia powder were used in the present study to separate a fermentation medium. The contribution of different components of this medium to the membrane fouling was investigated. Yeast extract (YE) was found to be the main reason for the membrane fouling during ultrafiltration (UF) of the fermentation medium. The electrostatic interactions: membrane/solutes were estimated measuring zeta (xi) potential of zirconia powders in contact with YE. Dynamic amino acid (AA) adsorption during ultrafiltration of yeast extract was assessed. Effect of pH, AA concentration, AA charge, and membrane charge modification on the retention and adsorption of free An existing in the YE were studied.