Hydrophobic ionic liquids for quantitative bacterial cell lysis with subsequent DNA quantification

DNA is one of the most frequently analyzed molecules in the life sciences. In this article we describe a simple and fast protocol for quantitative DNA isolation from bacteria based on hydrophobic ionic liquid supported cell lysis at elevated temperatures (120–150 °C) for subsequent PCR-based analysis. From a set of five hydrophobic ionic liquids, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide was identified as the most suitable for quantitative cell lysis and DNA extraction because of limited quantitative PCR inhibition by the aqueous eluate as well as no detectable DNA uptake. The newly developed method was able to efficiently lyse Gram-negative bacterial cells, whereas Gram-positive cells were protected by their thick cell wall. The performance of the final protocol resulted in quantitative DNA extraction efficiencies for Gram-negative bacteria similar to those obtained with a commercial kit, whereas the number of handling steps, and especially the time required, was dramatically reduced. [Figure: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00216-016-0112-x) contains supplementary material, which is available to authorized users.