Development of an in vivo methylation system for the solventogen Clostridium saccharobutylicum NCP 262 and analysis of two endonuclease mutants.

The genome of the biotechnologically important solventogenic Clostridium saccharobutylicum NCP 262 contains two operons coding for genes of presumed type I RM systems belonging to the families A and C. They represent a limiting factor for the development of transformation and conjugation protocols. We established an efficient triparental mating system to transfer DNA to C. saccharobutylicum by conjugation, which includes an in vivo methylation of the donor DNA. Furthermore we describe increased rates of conjugation in knock-out mutants of the restrictase subunits of both RM systems.