Overnight Incubation Technique for obtaining Transformable Bacillus subtilis Cells of Reproducible Competency

Abstract

THE use of Bacillus subtilis for DNA-mediated transformation investigations has found wide acceptance since the system was described by Spizizen¹ in 1958. In all bacterial transforming systems, technical difficulties arise in having available at the desired time a recipient bacterial population containing a high per cent of transformable (competent) cells. The usual preparation of B. subtilis recipient cells involves overnight incubation in broth, a 4-h period in growth medium followed by a 90-min period in transformation medium before maximum competence is obtained². These freshly prepared cells are highly competent, although the competence-level will vary and cannot always be predicted.