Screening and fermentation of cytidine-producing Bacillus subtilis mutants

Objective To derive a mutant which can increase the yield of cytidine from Bacillus subtilis which deficient in cytidine deaminase and observe the process of cytidine production of intermittent fed-batch fermentation.Methods(1) Inducing Bacillus subtilis CDS36(deficient in cytidine deaminase) by ultraviolet,the mutant was selected directionally and stepwisely on the agar plates containing 6AU and 5FCR.(2)Intermittent fed-batch fermentation:10% glucose was fed 48 hours later and 5% glucose was fed again 72 hours later,when the initial glucose concentration was 10%,the yield of cytidine was detected.Results(1)a mutant Bacillus subtilis CDS36-800-17 resisatnat to 6AU and 5FCR was otained.The critical resistance concentrations of 6AU and 5FCR were 1000mg/L and 800mg/L,respectively;2)The yield of cytidine was 5.58g/L and that of cytidine was 4.86g/L 96 and 120 hours after fermentation,Cytidine production was increased 20% through feed fermentation than through batch fermentation.Conclusion Cytidine overproducing mutant,Bacillus subtilis CDS36-800-17 with stable heredity and fermentation has been obtained,.Intermittent fed-batch fermentation methods can enhance the yoel of cytidine.