Competent Bacillus subtilis cells (repost)

Zhixiang Hu hu at
Thu Jul 29 10:49:13 EST 1993

I'm really a novice in cloning in B subtilis. What I need is simply to get
a protease expressed. I read a lot of papers dealling with transformation
of B subtilis with plasmids, but I still could not get good competent cells
by following the methods mentioned. It was said that covalently closed circular
(CCC) plasmid monomer is completely inactive in transformation. If the 
competent cells carry a plasmid that is homologous to the vector, then plasmid
monomer can transform. So, one has to prepare the competent cells which bear a
similar plasmid for use in ligated recombinant DNA.

Can some gentlemen and gentlewomen out there be kindly enough to provide me
with a practical protocol on competent cell preparation and transformation?

Thanks in advance!


Rutgers, NJ

e-mail: hu at

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