Efficient transformation of Lactobacillus sake by electroporation

Abstract

A procedure to transform intact Lactobacillus sake cells by electroporation was developed through a systematic examination of the effect of changes in various parameters on the transformation efficiency of Lact. sake 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 MgCI₂ in the expression medium. Under optimal conditions transformation efficiencies up to 10⁷ transformants (μg supercoiled DNA)^-1 were obtained. The optimized procedure was successfully applied to other Lact. sake strains and consistently yielded from 10⁴ to 10⁷ transformants (μg supercoiled DNA)^-1.