button: text-only site map
Flow Scheme of the Production Plant
diagram: flow scheme of the production plant
In excess of phenylalanine methyl ester the protected aspartame forms a poorly soluble carboxylate anion which precipitates from the reaction mixture. This makes it easy to remove by filtration.
The final steps are:

diagram: the final steps

More than 99.99% of the aspartame produced by this enzyme-catalysed process is the required sweet isomer.  It is hard to imagine any method other than enzyme catalysis giving such a high selectivity.