Research Of Conversion Of Orotic Acid To Uridine-5-monophosphate By Corynebacterium Ammoniagenes

Uridine-5-monophosphate (UMP) is an important medicine, pharmaceutical precursor andfood addition. A special aim of our research was to indicate the possibility that UMP could beproduced from orotic acid.The analysis of HPLC and MS-HPLC were employed to corroborate the conversion oforotic acid to UMP by Corynebacterium ammoniagenes. The results revealed that the yield ofUMP was 420mg/L when Corynebacterium ammoniagenes R248 was incubated at 25℃, pH5.0 in a medium containing 1g/L orotic acid,50μg/L biotin for 4 days,and 991mg/L of UMPwas accumulated in the enzymatic conversion reaction which consisted of 20g/L orotic acid,20%Corynebacterium ammoniagenes R248 cells.Five ml of the reaction mixture was poured intoa 250-ml flask and incubated at 32℃,pH 7.2 for 26 hours.The screening methods of streptomycin, kanamycin and pyrimidine analogue 5-FC wereused when the strain was treated with UV and N+.The mutant M14 of Corynebacteriumammoniagenes was obtained whose UMP yield was 7-fold higher than the parent strain R248.The conditions of fermentable and enzymatic conversion of M14 were optimized.In thefermentable conversion, 0.98g/L UMP was accumulated.The optimum enzymatic reactioncontained 20g/L orotic acid,30% wet cells,50g/L glucose, 15g/L KH2PO4.Five ml of thereaction mixture was poured into a 21×180mm tube and incubated at 32℃for 6 hours. The pHof the reaction mixture was maintained at 8.06. Ultimately,the yield of UMP was 2.1g/L.The fermentable and enzymatic conversion to accumulate UMP by Corynebacteriumammoniagenes R248, screening mutant with high capacity and optimizing the convertconditions are essential to research the conversion of orotic acid to UMP by Corynebacteriumammoniagenes further.