Recovery of L-lysine from L-lysine monohydrochloride by ion substitution using ion-exchange membrane

Ion substitution electrodialysis (ISED) consisting of two anion-exchange membranes and one cation-exchange membrane was performed to achieve efficient production of L-lysine from L-lysine monohydrochloride. Several experimental parameters including the operation voltage, the L-Lys center dot HCl concentration, and the initial pH of L-Lys center dot HCl solution were compared and discussed in terms of ionic transport. The Cl- removal ratio, the current density, the current efficiency, and the energy consumption were presented and analyzed. When the initial concentration of L-Lys center dot HCl is 0.6 mol L-1 and the constant voltage is 40 V. the removal ratio of Cl- reached 95.6%, the current efficiency 20.5% and the energy consumption 9.0 kW h kg(-1). Initial pH of L-Lys center dot HCl solution can affect the recovery ratio of L-Lys significantly. When the initial pH is kept at its isoelectric point, i.e. 9.74, the recovery ratio of L-Lys is to be maximized (93.2%). Elevating temperature can improve the electrodialysis process. (C) 2010 Elsevier B.V. All rights reserved.