Abstract: A process for the preparation of disodium Z-L-aspartate from fumaric acid, in whicha) fumaric acid is reacted with ammonia in an inert diluent in the presence of aspartase or aspartase-producing microorganisms to give ammonium L-aspartate thenb) the ammonium L-aspartate-containing solution is treated with sodium hydroxide, forming, depending on the amount of sodium hydroxide used, the mono- or disodium L-aspartate or a mixture thereof, andc) the eliminated ammonia is returned to a fumaric acid suspension, which is used as starting solution for further enzymatic reactions, and thend) the residual mono and/or disodium L-aspartate-containing solution is reacted with benzyloxycarbonyl chloride at a pH of between 9 and 14, with the simultaneous addition of sodium hydroxide, to form disodium Z-L-aspartate.