Quick and Cheap: Optimized Purification and Concentration of Bacteriophages Produced in Rich Culture Media

This protocol describes an easy, quick, cheap, and effective method for the purification and concentration of bacteriophages (phages) produced in rich culture media, meeting the quality criteria required for structural analyses. It is based on a tube dialysis system that replaces the classical but expensive and tedious density gradient ultracentrifugation step. We developed this protocol for the Oenococcus oeni bacteriophage OE33PA from its amplification to imaging by negative stain electron microscopy (NS-EM). The host bacterium, O. oeni, is a lactic acid bacterium that lives in harsh oenological ecosystems and grows only in rich and complex media such as Man-Rogosa-Sharpe (MRS) or fruit juice-based media in laboratory conditions. This raises experimental challenges in pure and concentrated phage preparations for further uses such as structure-function studies. Key features • Simple, rapid, and cheap, this method provides a fast and easy approach for efficient bacteriophage purification and concentration. • The method meets the structural study requirements of phage particles. • The method is compatible with bacteria that grow only in complex and rich culture media. • This protocol is also compatible with the purification of phages that produce low-titer lysates.