Optimization of the electroporation conditions for DNA Transformation of Staphylococcus carnosus

Abstract

In this paper, the optimization of electroporation method for Staphylococcus carnosus is investigated. The various factors for electrotransformation are evaluated, including bacterial growth phase, electroporation parameters, pBT2 plasmid DNA concentration and structure, the effect of protoplast or other cell wall-weakening treatments, and the prepulse incubation temperatures, etc. The primary optimized electroporation method is consisted of 60 μL electrocompetent cells and 800-1,000 ng plasmid DNA using the electroporation parameters of 21 kV cm-1 field strength, 50 ω resistance, and 25 μF capacitance by a Bio-Rad Gene Pulser Xcell™ system. Using this optimized method, three different plasmids (pBT2, pCX19, and pTX15) are successfully transformed into S. carnosus, and the transformation efficiencies are stationary at around 1 × 103 transformants per lg plasmid DNA. Our results indicate that this electroporation method can be generally applied for foreign DNA transformation into S. carnosus host. © Springer-Verlag Berlin Heidelberg 2014.