Phage Adsorption Assay

The phage adsorption assay was performed as previously described with some modifications (Kim and Ryu, 2012). Briefly, Pcc cells were harvested and suspended in TSB media (approximately 2~3 × 10⁸ CFU mL⁻¹). Phage POP72 was added to the bacterial suspension at an MOI of 0.01 and aliquoted in an equal volume to five microtubes. During the phage adsorption for 15 min at 28°C, each tube was centrifuged (16,000 × g, 4°C for 1 min) at the indicated time points, and the supernatants were immediately filtered (0.22 μm-pore-size filter). The number of remaining free phage particles in the filtrates was determined by the spot assay using Pcc27 as an indicator strain.