Enzymatic Synthesis Of Histamine

It was reported that histamine played a great role in the treatment of tumors.In 2008,dihydrochloride histamine produced by EpiCept was approved to be marketed by the European Union.It is used as a preventive treatment for acute myeloid leukemia with interleukin-2.At present,the histamine is synthesised by the chemical method,but it has some disadvantages,such as high temperature,high pressure,low conversion rate,low specificity and high cost.This study attempts to develop the high efficient and green synthesis tool called biocatalysis,which uses histidine decarboxylase(HDC)to catalyze the L-histidine to histamnie,laying a foundation for the industrial production of histamine.HDC(P.damselae JCM 8968:AB259289)was expressed successfully in E.coli.The experimental result revealed that the optimal induction time of HDC was 20 hours and the concentration of IPTG had a little effect on expression of HDC.By optimizing temperature and pH,the optimum reaction conditions are temperature 30? and pH 6.0.In order to further improve enzyme activity and reduce production cost,pACYCDute-?-HDC expression vector was successfully constructed.When the peptone concentration in the medium was increased to 2%,the bacterial concentration was increased 23.8%.The optimal induction temperature is 30?.40 ?mol/L IPTG is added when bacteria concentration is 1%.5 L fermentation process was established and the enzyme activity was increased to 10 U/mL(10% cell).Within a reaction time of 9 h and 2% cell breaking enzyme solution,the conversion rate of 10% histidine(w/w)reached 98.5%.