|The optimal reaction conditions were investigated to produce L-phenylalanine from transcinnamic acid and ammonia by Rhodotorula glutinis IFO 0559. The highest amount of L-phenylalanine was produced when the reaction mixture containing 200mM of traps-cinnamic acid, 4M of NH₄OH, 250mM of (NH₄)₂SO₄ 0.005% of cetylpyridinium chloride (pH 10.5) and 50㎎/㎖ of dry cell was used. Among the nonaqueous organic solvents, petroleum ether was the most effective on the production of L-phenylalanine. The optimal concentration of petroleum ether in the reaction mixture was 50%. Under the optimal conditions, 21.1g/ℓ of L-phenylalanine was produced in 12hr, and the yield was 63.9% based on transcinnamic acid.