1. The separation of the gluconic acid can be carried out by binding to an anion exchanger, conversion into a sparingly soluble salt or other derivative or separation according to other known physical or chemical methods. Gluconic acid formed can be separated by passage through an anion exchanger resin and thus removed from the equilibrium so that the reaction takes place quickly and quantitatively.
2. Gluconic acid in form of liquid sodium gluconate is concentrated and crystals are separated by filtration and dried at 37° C.