Study On Inhibition Of Escherichia Coli And Its Biofilm By Compound Electric Field

In the 21 st century,China's agriculture has developed rapidly,and the agricultural production technology has changed with each passing day.With the gradual elimination of traditional high pollution,high energy consumption and low efficiency production methods,high-voltage electrostatic field technology is widely used in crop cultivation,livestock breeding and other fields with its advantages of no secondary pollution after treatment.In this paper,the effect of high voltage electrostatic field on “E.coli and its biofilm was studied.Firstly,the data of the lethal rate of E.coli were analyzed by using the high voltage electrostatic positive electric field,high voltage electrostatic negative electric field and high voltage electrostatic compound electric field in different voltage intensity and different time.At the same time,the growth curve of E.coli after the treatment of high voltage electrostatic field was studied by using different concentration of sodium chloride culture medium,and the conductivity was measured Fourier infrared spectroscopy was used to verify the results of the experiment.Finally,the E.coli biofilm was treated by high-voltage electrostatic composite electric field.The results showed that the high-voltage electrostatic field had a significant effect on the death rate of E.coli,the electrical conductivity of E.coli increased after the treatment,the intensity of infrared spectrum increased,and the high-voltage electrostatic field had an effect on the formation,reproduction and shedding of the biofilm of E.coli.The main contents and conclusions of this paper are as follows:1.To study the effect of different voltage and time on the lethal rate of E.coli.High voltage positive,negative and complex electric fields were used to treat the coliform bacteria solution.The conditions were as follows: the distance between the sample table and the electrode line was 1cm,the temperature was 20°C,and the action time and voltage were changed.The statistical analysis showed that the change of electric field voltage and treatment time had a significant effect on the lethal rate of coliform bacteria.The higher the voltage is,the longer the treatment time is,the higher the lethality is.The voltage is 30 kv,the treatment time is 1h,and the lethality of E.coli reaches 30.16%.The high voltage electrostatic positive electric field slightly promotes the growth of E.coli at 10 kv,the lethality is-17.68%,and the voltage is 15kv-30 kv.The longer the treatment time is,the higher the electric field voltage is,the higher the lethality is.When the treatment time is 1h,the lethality is higher After the treatment of high-voltage electrostatic field,the lethal rate increased significantly with the prolongation of the treatment time of high-voltage electrostatic field,and the lethal rate reached 60.63% under the condition of 12 h treatment time and 20 kv electric field voltage.2.The sublethal rate of E.coli was studied and the growth curve of E.coli was measured.Setting 1%,2%,3%,4% concentration of sodium chloride to select the medium,the concentration of sodium chloride in normal LB medium is 1%,2% and 3% concentration of sodium chloride can kill the injured E.coli,E.coli can not survive on the 4% concentration of sodium chloride medium,the longer the electric field treatment time,the higher the sublethal rate,and the sublethal rate after the electric field treatment for 12 h is 25.96%.The results showed that the growth of E.coli was slow after treatment,and the OD value of the stable period was significantly lower than that of the untreated solution.The results showed that the high-voltage electrostatic field had an effect on the metabolism of E.coli.3.Conductivity and FTIR analysis.The conditions are as follows: the distance between the sample table and the electrode line is 1cm,the temperature is 20°C,the electric field intensity and the action time of the high voltage electric field are changed,the electric conductivity and the spectrogram are changed.The electric conductivity increased with the increase of voltage and action time of high-voltage electrostatic negative electric field.The electric conductivity reached 38.60ms/cm at the voltage of 20 kv and treatment time of 1h.The electric conductivity reached 67.10ms/cm after treatment of high-voltage electrostatic compound electric field for 12 h,which was 28.77ms/cm higher than that of the control group.The FT-IR spectrum of E.coli treated by high-voltage electrostatic field showed that the high-voltage electrostatic field had an effect on the cell wall of E.coli,but the peak intensity was higher than that of the control group.4.To explore the effect of compound electric field on E.coli biofilm.Compared with the control group,the growth and reproduction of E.coli biofilm treated by high-voltage electrostatic compound electric field were affected,the growth was slower,and it was easier to fall off.