Efficient transformation of Lactobacillus sake by electroporation.

A procedure to transform intact cells by electroporation was developed through a systematic examination of the effect of changes in various parameters on the transformation efficiency of strain 64F. The most critical factors were found to be the electrical parameters, the composition of washing and electroporation/storage solutions, and the presence of MgCI in the expression medium. Under optimal conditions transformation efficiencies up to 10 transformants (μg supercoiled DNA) were obtained. The optimized procedure was successfully applied to other strains and consistently yielded from 10 to 10 transformants (μg supercoiled DNA).