HI DEAR COLLEAGUE, TRY ELECTROPORATION ACCORDING TO METHODS, 5, 79-85 (1993). I MY HANDS IT WORKED WITH THE STATED EFFICIENCY (1 X 10-6/MKG OF PLASMID). I DO NOT KNOW YOUR STRAIN, BUT RELATIVELY SMALL NUMBER OF LABORATORY STRAINS ARE EASY TO SPHEROPLAST AND YOUR KIT IS PROBABLY TITRATED ON ONE OF THEM. GOOD LUCK ANDREI POPOV