Abstract: The yeast strain with high activity of producing phenylalanine ammonia-lyase, SA1, was screened from soil. The optimum enzyme productivity and conditions for the conversion of trans-cinnamic acid into L- phenylalanine were determined. The results showed that the production of enzyme was kept high by addition of L-phenylalanine, L-tyrosine and isoleucine, where L- tyrosine was optimum. The optimal parameters of the conversion reaction were: 2.0% trans-cinnamic acid, NH4HCO3:NH•3H2O (W:V)=4:4, pH10.6, 34℃, and the time of reaction 8h. The enzyme activity was kept stable by the addition of glycerol.

Key words: L-phenylalanine, phenylalanine ammonia-lyase, trans-cinnamic acid