An economical large-scale procedure to purify Micrococcus plasmid DNA.

A reproducible and economical procedure for obtaining a large yield of highly purified covalently closed circular (ccc) plasmid DNA from an industrially important strain of Micrococcus is described. The procedure adopted here departs in several ways from commonly used protocols for isolation of plasmid DNA from Gram (positive) and Gram (negative) bacteria. The plasmid DNA prepared by this procedure is free of contaminants and is pure enough to be used for electron microscopy, DNA transformation, sequencing, in vitro transcription and mutagenesis.