Sterilization of Escherichia coli cells by the application of pulsed magnetic field

Abstract： The inactivation of microorganisms by pulsed magnetic field was studied. It was improved that theapplication of electromagnetic pulses evidently causes a lethal effect on E. coli cells suspended in phosphate buffersolution Na2 HPO4 / NaH2 PO4 (0.334/0.867 mmol/L). Experimental results indicated that the survivability( N/N0; whereN0 and N are the number of cells survived per milliliter before and after electromagnetic pulses application,respectively) of E. coli decreased with magnetic field intensity B and treatment time t. It was also found that themedium temperatures, the frequencies of pulse f, and the initial bacterial cell concentrations have determinateinfluences in destruction of E. coli cells by the application of magnetic pulses. The application of an magneticintensity B = 160 mT at pulses frequency f = 62 kHz and treatment time t = 16 h result in a considerable destructionlevels of E. coli cells ( N/N0 = 10-4 ). Possible mechanisms involved in sterilization of the magnetic field treatmentwere discussed. In order to shorten the treatment time, many groups of parallel inductive coil were used. Thepracticability test showed that the treatment time was shortened to 4 h with the application of three groups of parallelcoil when the survivability of E. coli cells was less than 0.01%; and the power consumption was about 0.2 kWh/m3 . 作 者： LI Mei    QU Jiu-hui    PENG Yong-zhen   作者單位： LI Mei(Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China;School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China)

QU Jiu-hui(Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China)

PENG Yong-zhen(School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China) 

期 刊： 環境科學學報(英文版)  ISTICSCI   Journal： JOURNAL OF ENVIRONMENTAL SCIENCES  年，卷(期)： 2004, 16(2)  分類號： X703  Keywords： Escherichia coli bacteria    pulsed magnetic field    induced current    cell membrane