Production of Nucleic Acid-related Substances by Fermentative Processes

Part XXXVIII. Production of Uridine 5'-Monophosphate and Orotidine 5'-Monophosphate by Brevibacterium ammoniagenes

Abstract

During the cource of the investigation of ribotidation of purine and pyrimidine bases by Brevibacterium ammoniagenes ATCC 6872, it was found that a large amount of uridine 5'-monophosphate (UMP) was accumulated in the culture broth when the organism was incubated in a medium containing uracil or orotic acid. The yields of UMP were 83% (4.8mg/ml) from uracil and 10000 (4.3mg/ml) from orotic acid when each substrate was added at the concentration of 2mg/ml.
Addition of 6-azauracil or 5-hydroxyuracil to the culture of the organism during cultivation led to the accumulation of both orotidine 5'-monophosphate (OMP) and UMP. The accumulation of OMP seemed to be due to the inhibition of OMP decarboxylase (E. C.4.1.1.23) by the ribotide formed from each base. The OMP accumulation was enhanced by the addition of orotic acid in addition to 6-azauracil. When 6-azauracil was added to the medium before inoculation, UMP was predominantly accumulated, and when it was added after one day incubation, OMP was predominantly accumulated. A largest accumu-lation (3.6mg/ml) of OMP was obtained when 6-azauracil was added on the 1st day and orotic acid was added on the 3rd day.
UMP and OMP accumulated in the medium were isolated from the cultured broth and identified by usual methods.