Lactococcus Phage Characterization Protocol

Bacterial strains and phages used in this study are listed in Table 1. Lactococcal strains were grown at 30 °C without agitation in M17 broth (Oxoid Ltd., UK) supplemented with 0.5% glucose. Phage lysates for the various biological characterisation assays were induced from (at least) three separate overnights of NZ9000-Cro_t712 lysogenized with TP901-1erm, or a particular mutant derivative using 0.5 μg/ml mitomycin C when the growing cultures reached an optical density at 600 nm (OD600) of approximately 0.2. Polyethylene glycol 8000 (PEG 8000) precipitation of phage particles (or component parts) of the TP901-1erm phage or a particular mutant derivative, and their subsequent purification, was performed as described previously31 (link).