Abstract: This invention relates to an improvement in a method for manufacturing dipeptides by coupling N-blocked aspartic acid and a phenylalanine lower alkyl ester in a medium containing a water-miscible organic solvent mixture in the presence of an immobilized metallo-protease so that a continuous reaction is established with stable enzyme activity.

Abstract: A process for the preparation of .alpha.-L-aspartyl-L-phenylalanine methyl ester in high yield, which comprises the steps of esterifying L-phenylalanine with methanol while undergoing continuous evaporation to remove the water formed during esterification, coupling the produced L-phenylalanine methyl ester with N-formyl-L-aspartic anhydride, deformylating the produced N-formyl-L-aspartyl-L-phenylalanine methyl ester, crystallizing the formed .alpha.-L-aspartyl-L-phenylalanine methyl ester as .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloric acid salt, recovering the first .alpha.-L-aspartyl-L-phenylalanine methyl ester hydrochloric acid salt, esterifying .alpha.-L-aspartyl-L-phenylalanine in the filtrate to produce the second .alpha.-L-aspartyl-L-phenylalanine methyl ester, and combining the first and second .alpha.-L-aspartyl-L-phenylalanine methyl ester product.

Abstract: An immobilized fructosyltransferase enzyme is prepared by providing a porous or macroporous anion exchange resin having at least 1.0 m.sup.2 /g of internal surface, at least 0.1 ml/g of total porous volume, a spherical radius of 20-2,000 angstroms, and a nominal ion-exchange capacity of at least 1.0 meq./g of wet resin, adding to the ion-exchange resin a solution of fructosyltransferase enzyme derived from a microorganism of the genus Aureobasidium, Aspergillus, Fusarium, or Gloeosporium at a pH value of about 3-8, filtering and wind-drying the absorbed resin, and storing it in a cool place. A bifunctional cross-linking agent may be present in the solution of fructosyltransferase enzyme.

Abstract: A process for purification and recovery of phenylalanine from a microbial fermentation broth containing phenylalanine which comprises providing a zinc salt of phenylalanine at a pH of 7-9, adding acid at a pH of 4-7, and separating precipitated phenylalanine.