Plasmid transformation of Clostridium perfringens by electroporation methods

Two electroporation methods were compared and modified to improve the frequencies of transfer of plasmid DNA into Clostridium perfringens. A plasmid shuttle vector, pSB92A2, containing chloramphenicol and ampicillin resistance genes and a clostridial origin of replication isolated from a cryptic C. perfringens plasmid, was constructed and fully introduced into C. perfringens by both electrotransformation methods. Modifications which improved frequencies by 15–28 fold are described and may improve frequencies sufficiently for some vector/host combinations to consider the future use of more direct cloning strategies for the clostridia.