Knockout of the cdd Gene in Bacillus subtilis and its Influence on Cytidine Fermentation

Objective:To knockout cytidine deaminase gene of original strain for blocking pyrimidine metabolic flux to flow from cytidine to uridine and uracil,and to select cytidine producing bacteria.Methods:The cytidine deaminase gene cdd of Bacillus subtilis TS8 was knockouted by using homologous recombination,its resistance and production were verified through stability experiment,and the level of cytidine production between mutant and original strain was compared.Results:The mutant B.subtilis TSb accumulated cytidine 1.72 g/L after 72 h of fermentation,increasing by 44.19%compared with original strain.It also had stable heritage.Conclusion:cdd mutant B.subtilis TSb can enhance cytidine production,blocking pyrimidine metabolic flux to flow from cytidine to uridine and uracil significantly.