Process development and optimisation of lactic acid purification using electrodialysis

Cell free sodium lactate solutions were subjected to purification based on mono- and bi-polar electrodialysis. Lactate concentration in the product stream increased to a maximum of 15% during mono-polar electrodialysis. Stack energy consumption averaged 0.6 kW h kg −1 lactate transported at current efficiencies in the 90% range. Under optimum feed concentration (125 g l −1) and process conditions (auto-current mode with conductivity setpoints of minimum 5 and maximum 40 mS cm −1), lactate flux reached 300 g m −2 h −1 and water flux were low for mono-polar electrodialysis averaging 0.3 kg H 2O per M lactate transported. Glucose in the concentrate stream solutions was reduced to