THE TRANSFORMATION OF TRANS-CINNAMIC ACID INTO L-PHENYLALANINE BY Rhodotorula Glutinis

An enzymatic method using L-phenylalanine ammonia-lyase (PAL) of Rhodotorula glutinis for the transformation of trans- cinnamic acid(t-Ca) to L-phenylalanine was investigated in the paper, majoring in isolation of strains conditions of producing L- phenylalanine ammonia-lyase and conditions of transformation. The optimum medium for PAL production was composed of 5.0 gIL glucose, 10.OgIL soybean hydrolysate and 0.5g/L KH2PO4, pH 5.5. The cell was incubated at 280C with 5.0% seed culture on a shaker operated at l7Orlmin, L-Tyr was added until 0.5 g L at 1 5h and the cell was collected after 21 h, the enzyme specific activity as high as 19.0 mU ?mg~?was obtained. The optimum transformation conditions were 1.0% 1-Ca, 6mol/L ammonia, NH3H2O NH4HCO3=1 1 :5(VIW), a =4, 0.005% cetylpyridinium chloride, pHlO.0, 300C. Adding mercaptoethanol in bioreaction mixture, 2 -sparging, removing of CL and low temperature centrifugation resulted in good catalyst stability. Keeping concentration of t-Ca in 1.0% for 48h by flow-adding 1-Ca, 73.3% t- Ca was transformed to L-Phe, and 29.4g/L L-Phe was obtained.