| High-voltage pulse sterilization is a new non-thermal sterilization technology, which is high intensity pulsed electric field applied causes the membrane of bacteria and other microorganisms to produce perforations, intracellular material outflow, or to the nature of the biologically active substance in cells is changed so that the microbial death or apoptosis program. Different types of microbial cell structure and the presence of biologically active substances constitute a big difference, so that there is different from those in response to a pulsed electric field, making the damage mechanism of microorganisms under high intensity pulsed electric field is extremely complex. On the development of the three high-voltage pulse source ?s level,100ns grade level and ns grade level pulse width, E. coli, yeast and Candida albicans were pulsed electric field sterilization experiments as a subject, focusing on the role of pulsed electric field and bacterial survival time Relationship rate and biological activity, the differences affect the inactivation efficiency and cell structure of a preliminary study.The main research work is as follows:(1) Established cell circuit model to analyze the changes in low concentrations in the cell suspension membrane voltage direct current electric field is applied, time-varying electric fields and pulsed electric field, and on the next ?s level,100ns grade level and ns grade level pulse width conditions cell membrane voltage simulated.(2) Developed three high-voltage pulser with the width ?s level,100ns grade level and ns grade level.(3) Systematically study ?s level,100ns grade level and ns grade level pulsed electric field on bacteria killing effect of prokaryotes and eukaryotes bacteria. In Escherichia coli, yeast and Candida albicans is a subject, multi-middleweight respectively diluted culture plate count assay viability, cell viability using the MTT assay. Survival rates reflect the impact of an electric field on bacteria detection capacity, reflecting the field activity in direct killing ability of bacteria. The results are as follows:? Tolerance threshold for the presence of bacteria pulsed electric field, when the electric field strength is below the threshold, the number of pulses increased not significantly reduce bacterial survival and activity. When the electric field intensity is above the threshold, with the electric field strength rises linearly decrease bacterial survival.? Bacteria is resistant to the threshold electric field and is closely linked to the pulse width, the pulse width is smaller, the higher the electric field tolerance threshold of bacteria. Under the same conditions of electric field intensity, pulse width with increased microbial survival decreased exponentially.? Electric field time differences and activity of prokaryotes and eukaryotes bacterial viability of the electric field for different types of bacteria are called upon to achieve selective destruction. ?s level pulses can significantly reduce prokaryotes and eukaryotes bacterial viability, but also the prokaryotic cell bacterial activity decreased; under one hundred ns pulsed electric field is no significant difference in killing eukaryotic cells and prokaryotic cells of bacteria; ns stage Under pulses, eukaryotic cells viability and activity of the bacteria were significantly reduced, but prokaryotic cells to kill bacteria ineffective.? With the number of pulses increased bacterial survival reduced exponentially, but little change in bacterial cell activity.In summary, the results show that the high-voltage pulse sterilization is a highly effective sterilization method for prokaryotic cells and eukaryotic cells of bacteria sterilization effect and the pulse width, the field strength, the number of pulses and other parameters are closely related, survival and activity of the bacteria for which there are differences with different width, is expected to achieve different types of bacteria to selectively kill. |
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