Abstract:METATOOL soft ware was applied to analyze the cytidine biosynthesis pathway in Bacillus subtillis TZM1012．The results was as follows: PRPP and oxaloacetic acid were found to be the key nodes in cytidine biosynthesis pathway and low dissolved oxygen concentration in the medium-term and last periods of fermentation was an important precondition of cytidine biosynthesis. The highest theoretical yield of cytidine was 0.28 and cytidine yield could increased by 15.8% if the dissolved oxygen concentration in fermentation broth was of 5%~10%. According to the analysis of metabolic pathway of cytidine biosynthesis, the yield of cytidine can be greatly improved by changing the environmental factors.
