Abstract: Disclosed is a method of crystallizing .alpha.-L-aspartyl-L-phenylalanine methyl ester, which is a sweetening agent substituting sugar and commonly referred to as aspartame. An aspartame solution is sprayed and droplets of the solution fall downward. Cold airflow is blown to the falling droplets of the aspartame solution to cool them. The aspartame dissolved in the droplets crystallizes, and the slurry including the aspartame crystals and the remaining solution is collected for further processes. Also disclosed is a crystallizer for cooling crystallizing the aspartame solution with this method. The crystallizer has an atomizer for spraying the aspartame solution supplied thereto and an air inlet and an air outlet. The cold air is blown into the crystallizer through the air inlet, cools the droplets of the aspartame solution, and is discharged through air outlet.

Abstract: Disclosed is a method of crystallizing .alpha.-L-aspartyl-L-phenylalanine methyl ester, which is a sweetening agent substituting sugar and commonly referred to as aspartame. An aspartame solution is gradually cooled by heat exchanging with a coolant passing by with each other in the opposite direction. This enables that the heat-exchange between the aspartame solution and the coolant occurs at small and almost constant temperature difference. The cooling crystallization with such small temperature difference provides coarse and uniform aspartame crystals. Also, the aspartame solution is forcedly stirred such that crystals and crystal lumps formed are not re-dissolved or broken down. The forced stir of the solution makes the crystals and the lumps be suspended in the solution, which prevents formation of scales on any surfaces.

Abstract: Disclosed is a method of cooling and crystallizing .alpha.-L-aspartyl-L-phenylalanine methyl ester, which is a sweetening agent, commonly referred to as aspartame. An aspartame solution is cooled such that the solution is flown while being continuously in thermal contact with a coolant. As the cooling of the aspartame solution by the thermal contact with the coolant proceeds, the temperature difference between the aspartame solution and the coolant remains substantially constant. The coolant flows in the opposite direction as the aspartame solution flows and cools an upstream part of the aspartame solution as the coolant flows downstream.

Abstract: An E. Coli which can produce phenylalanine and which has an optimum phenylalanine production capability at a temperature of 30.degree. to 35.degree. C., and a process for preparing L-phenylalanine by use of the novel E. coli MWPEC 12-45 (ATCC 67460).