Effect Of High Voltage Pulsed Electric Field On Microbial Growth And Game Theory

There are a large number of Escherichia coli growing and reproducing in livestock and poultry houses in China,which causes various diseases of livestock and poultry,and cause huge economic losses to livestock and poultry industry.In order to solve this problem,high voltage pulsed electric field and Bacillus subtilis were used to treat Escherichia coli.This paper constructs the growth model of two bacteria,explores the treatment effect of high-voltage pulsed electric field on two bacteria,establishes the favorable and adverse environment game model between two bacteria,and carries out fractal simulation test before and after treatment by high-voltage pulsed electric field,which provides a good demonstration for the influence of high-voltage pulsed electric field on the growth and development of bacteria and the prediction of bacterial growth.The conclusions are as following:(1)The growth curves of Escherichia coli and Bacillus subtilis were determined by spectrophotometry,and the Gompertz model was used to fit the growth curves.(2)When the treatment time was 1 h and the voltage was 10 KV,the lethal rates of positive and negative high voltage pulsed electric fields to Escherichia coli were 20.80% and 25.92% respectively,and the lethal rates to Bacillus subtilis were 20.43% and 21.75% respectively;When the treatment time was 1 h and the frequency was 300 Hz,the lethal rates of positive and negative high voltage pulsed electric fields to Escherichia coli and Bacillus subtilis were 18.74% and 27.81%,18.11% and 23.87%,respectively;When the treatment time was 1 h and the duty cycle was 75%,the lethal rates of positive and negative high-voltage pulsed electric fields to Escherichia coli and Bacillus subtilis were 19.85% and 29.58%,22.92% and 24.74%respectively;When the voltage was 10 KV and the time was 6 h,the lethal rates of positive and negative high voltage pulsed electric fields to Escherichia coli were 63.27% and 73.61% respectively,and the lethal rates to Bacillus subtilis were 60.44% and 61.31% respectively.(3)Both positive and negative high voltage pulsed electric fields have significant lethal effects on Escherichia coli and Bacillus subtilis.The optimal parameters can be set as follows: voltage: 10 KV;frequency: 300 Hz;duty cycle: 75%.(4)In the game of favorable situation,the coefficient of game relationship is a12=0.4880;a21=-0.3974,which indicates that Bacillus subtilis has inhibition on Escherichia coli;in adversity game,a12=0.1555 and a21=-0.012 further show that Bacillus subtilis has more significant inhibition on Escherichia coli.(5)The DLA model is used to simulate on MATLAB.Under normal growth condition,the fractal simulation fitting accuracy of Escherichia coli and Bacillus subtilis were R2 = 0.98821 and 0.973 respectively;after high voltage pulsed electric field treatment,the fractal simulation fitting accuracy of Escherichia coli and Bacillus subtilis were R2 = 0.93156 and 0.97097 respectively.