I have been working on B. subtilis transformation for a while, and despite many efforts and the use of different protocols I have not succeeded in doing it so far.

I used the well known protocol called the "Paris method" and many other protocols from different laboratories but, I did not see any colony after transformation.

So does anyone know about natural competence of B. subtilis and the best and most efficient protocol that I can use? if there is any useful tip, please share it with me.