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The Synthesis Of Compatible Solute And Resistant Research In Escherichia Coli

Posted on:2016-11-09Degree:MasterType:Thesis
Country:ChinaCandidate:C GaoFull Text:PDF
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In order to obtain a E.coli recombinant strain who can regulate the synthesis of the compatible solute (such as ectoine and trehalose used in this research) according to the change of the pressure conditions, seven promoters are collected. They are pCP6, Ibp, pHe, Fic, Gron, Degp and sta69. The result that the synthesis of ectoine could reduce the tolenrance to high salinity in E.coli was adverse with the previous result that adding ectoine into the medium could promote the growth of E.coli. The reason was analyzed in three contexts:the protein expression, the toxicity of intermediates and the metabolic disturbance, which suggested that the lack of DAP due to metabolism competition was one of the important factors. When trehalose is selected. the recombination strains whose trehalose synthesis controlled by promoters Ibp, pHe and Fic exhibited more tolerance to osmotic stress which was verified by some phenomenon that lag phase is shorter, the growth in log phase is faster and the biomass in stationary phases is higher.In order to product high purity of trehalose to satisfy the need of medicine, a engineering strain is constructed by the method of Synthetic biology conbined with Whole-cell catalysis. The result suggested that knockouting of the trehalose degradative gene(? TreA- TreC- TreF) and glucose metabolic gene (? Zwf) can significantly increase trehalose synthesis up to 7g L-1 finally.
Keywords/Search Tags:stress, tolerance, promoter, compatible solute, ectoine trehalose synthetic biology, whole-cell catalysis
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