Mutagenesis And Fermentation Of A2,3-BD Producing Strain Of Enterbocter Cloacae

2,3-Butanediol (2,3-BD) is one of important bulk chemicals, which exhibits a wide range of potential utilizations in medicines, foods, chemicals and other fields. Until now, the price of2,3-BD is very high, as the production methods mainly based on oil and other non-renewable resources. A lot of strains can produce2,3-BD, the Klebsiella and Enterobacter have the higher yield of2,3-BD. Klebsiella is a kind of conditioned pathogen, which is limited it’s use in the industrial application. E. cloacae not only has the advantages of Klebsiella, such as the availability of substrate, high substrate utilization, at the same time, as the microorganisms used for industrial production applications is very safe. But the drawback is that the2,3-BD production is not very high. In this paper, The mutagenesis of E.cloacae was occurred under the treatment of dielectric barrier discharge plasma coupled with diethyl sulfate, and a positive mutant strain (E. cloacae DLM) which could produce2,3-butanediol at high concentration was obtained. The concentration of2,3-butanediol reached111.14g/L under fed-batch fermentation by E. cloacae DLM, which was20%higher than that of the wild strain.First, the condition of mutagenesis was decided:First,2%(v/v) diethyl sulfate was used to treat1mL bacterium with5min, and then put500uL of the bacterium in the plasma, and adjusted the voltage of the plasma generating device for25kV,1.2mA, the electrode spacing of3mm. At last, a mutant strain was screened, which named as E. cloacae DLM. Through flask fermentation, the concentration of2,3-butanediol reached111.14g/L, which was40%higher than that of the wild strain. The concentration of2,3-BD reached111.14g/L under fed-batch fermentation by E. cloacae DLM, which was30%higher than that of the wild strain.Then, the optimum conditions for2,3-BD production by E.cloacaeDLM were investigated. The results showed that the optimum conditions of fermentation were0.10vvm of air flow,5.8of pH value by using fed-batch fermentation. The concentration of2,3-butanediol reached125.9g/L under fed-batch fermentation by E. cloacae DLM, which was43%higher than that of the wild strain. The concentration of2,3-BD reached111.62g/L under fed-batch fermentation by using Inulin as carbon source, which was27%higher than that of the wild strain. The concentration of2,3-BD reached107.18g/L under fed-batch fermentation, which was22%higher than wild strain. At last the heritage stability of this strain was confirmed. The results showed that the strain we mutated is a potential strain for industrial production of2,3-BD.