Abstract: An indirect acidulation process for producing glutamic acid from an aqueous feed containing a glutamate resulting from fermentation includes: a) contacting an aqueous feed stream at an elevated temperature with a weak acid cation exchanger (WACE) which is at least partially in its acid form, whereby a part of the cations in the solution is taken up by the cation exchanger and protons are introduced into the solution; b) contacting a second aqueous feed containing glutamate and cations at an elevated temperature with a strong acid cation exchanger (SACE) that is obtained from a subsequent step and carries cationic glutamate, whereby the cationic glutamate is transferred into the solution and most of the cations in the second aqueous feed are taken up by the SACE; c) crystallizing glutamic acid from the effluent of step (b); d) contacting the mother liquor of step (c) with the SACE which is at least partially in its acid form whereby cationic glutamate is bound; e) utilizing the SACE obtained in step (d) in ste

Abstract: The invention provides a process for the preparation of aspartic acid via a fermentation process for the preparation of ammonium fumarate, wherein the pH of the fermentation broth is controlled by the addition of a calcium base to produce a calcium fumarate precipitate, characterized in that ammonium fumarate is produced by separating the precipitated calcium fumarate from the fermentation broth, and reacting the same with a reagent selected from ammonia, ammonium carbonate, ammonia in combination with CO.sub.2 and mixtures thereof, to form ammonium fumarate and a co-product selected from calcium carbonate and calcium hydroxide, wherein the energy of indirect neutralization of fumaric acid by ammonia serves as the driving force for the conversion of calcium fumarate to the desired ammonium fumarate product and for the regeneration of a calcium base reagent, and wherein diammonium fumarate is enzymatically converted to ammonium aspartate and acidulated to from aspartic acid.

Abstract: A method for producing xylitol from D-glucose, D-fructose, D-galactose or mixtures thereof, characterized in that it comprises the steps of:a. oxidation of the starting material to an intermediate that consists mainly of L-xylonic acid, D-arabinonic acid, D-lyxonic acid or a mixture of at least two of said acids, whereby said acids are free or in the form of their salts, lactones or O-formyl derivatives;b. treatment of said intermediate with a hydrogenation catalyst and hydrogen gas in one or several steps to a product consisting mainly of xylitol or a mixture of xylitol, arabinitol and ribitol;c. and, if necessary, separation of xylitol from said product and, if said product consist mainly of said mixture of pentitols, feeding of the fractions of arabinitol and ribitol back to the preceding reaction step b.