Recent biotechnological developments of electropulsation. A prospective review.
During the last 25 years, basic research has improved our knowledge on the molecular mechanisms triggered at the membrane level by electric pulses. Applied aspects may now be used under safe conditions. Electropulsation is known as a very efficient tool for obtaining gene transfer in many species to produce genetically modified organisms (GMO). This is routinely used for industrial purposes to transfer exogenous activities in bacteria, yeasts and plants. The method is simple and of a low cost. But electropulsation is not limited to this application for biotechnological purposes. It is known that the field-associated membrane alterations can be irreversible. The pulsed species cannot recover after the treatment. Their viability is strongly affected. This appears as a very promising technology for the eradication of pathogenic microorganisms. Recent developments are proposed for sterilization purposes. New flow technologies of field generation allow the treatment of large volumes of solution. When high flow rates are used, microorganisms are submitted both to a hydromechanical and to an electrical stress. The synergy of the two effects may be present when suitable pulsing conditions are chosen. Several examples for the treatment of domestic water and in the food industry are described. Walled microorganisms are affected not only at the membrane level. We observed that alterations are present on the cell wall. A very promising technology is the associated controlled leakage of the cytoplasmic soluble proteins. Large dimeric proteins such as beta-galactosidases can be extracted at a high yield. High volumes can be treated by using a flow process. Extraction of proteins is obtained with many systems including mammalian cells.