A New Process On Production Of D-Phenylalanine

D-Phenylalanine(D-Phe) can be widely used in food, cosmetic, medical industry and so on. In this paper the property, application and preparation developments of D-Phe are reviewed. Moreover, a new process to produce of D-Phe by coupling reaction and separation is systematically studied and firstly developed in China on the basis of one enzyme-one acid method, and lots of experiments verify it is viable and reliable. The main contents and innovations are as follows:N-Carbamoyl-D-PhenylaIanine(Nc-D-Phe) is synthesized by enzymatic method. At first D,L-benzylhydantoin(D,L-BH) is converted to produce Nc-D-Phe by D-hydantoinase(D-Hyn). Results show that the activity of Z)-Hyn is fairly high when the mass ratio of wet cells to D,L-BH is 1:1 and pH value is equal to 9.5 at 38℃, and yield of Nc-D-Phe is above 80%. Furthermore, D,L-BH is fed in small amount regularly in fed-batch reaction can accelerate enzymatic reactive rate. The effective ratio of wet cells to D,L-BU is up to 1:2.5, utilization rate of D-Hyn is enhanced, and the cost is reduced.Nc-D-Phe is hydrolyzed to D-Phe by nitrous acid. We hydrolyze Nc-D-Phe to D-Phe using hydrochloric acid and sodium nitrite in place of unstable nitrous acid. The rational molar ratio of sodium nitrite to Nc-D-Phe is 1.2:1, dripping rate of sodium nitrite solution is about 10mL/min, and reaction time is 3 hours at 15℃. Then D-Phe is separated by strong acidic resin. According to optimization of reactive process, yield of D-Phe is above 80%.A new process to produce D-Phe by coupling reaction and separation is developed firstly in China. Hydrolyzation of Nc-D-Phe and separation of D-Phe are coupled by strong acidic resin not only providing an acidic environment for hydrolyzation, but also absorbing D-Phe. In this process salt can't produce in large amount, process is simplified, and cost is reduced. The total yield of D-Phe is 70% appropriately. In addition, the present study is not reported previously in China.