Electrotransformation of Clostridium acetobutylicum ATCC 824 using high-voltage radio frequency modulated square pulses

Molecular biological improvement of industrial solventogenic clostridia cou ld be enhanced by a higher efficiency of electrotransformation. In this res earch, we used a new approach to determine the frequency spontaneously gene rated by Clostridium acetobutylicum ATCC 824 cells during the application o f a square high-voltage pulse. Once the frequency of 100 kHz was determined we transformed clostridial cells with pSOS84 plasmid DNA using radio-frequ ency modulated high-voltage square pulses (electric field strength 12 kVcm( -1); pulse duration 22.5 ms; frequency of pulse modulation 100 kHz) to reac h an efficiency exceeding 10(6) transformants mu g(-1) of plasmid DNA. We p ropose a possible role for cellular membrane structures in affecting the tr ansformation yield.