Isolation of cyanophages by liquid enrichment assay
Prefilter at least 3 L water sample through a glass fiber filter .
Filter sample through 0.2 µm or 0.45 µm low protein binding PVDF filter .
Dispense the filtered water samples ( e . g . , 0.5 L or more ) into culture vessels , e . g . , 1 L or larger Erlenmeyer flasks .
Add nutrients to the filtered water to support growth of the target cells .
Seed the filtered water with 1 % to 10 % v / v of host culture .
As a control , replace the filtered environmental sample with virus - free ( 0.02 µm filtered or heat - killed ) water sample .
Incubate the flasks at the temperature and light conditions appropriate for the cyanobacteria and look for signs of lysis .
Remove an aliquot of the enrichment culture , and pellet remaining cells by centrifugation ( e . g . , 20 minutes at 6000g ) .
Filter the supernatant through a 0.22 µm or 0.45 µm PVDF filter .
Store the lysate at 4°C until further analysis .
Verify the presence of lytic phages by liquid assay ( or plaque assay ) .
To propagate / amplify the lytic agent , the liquid bioassay is repeated using the putative lytic agent as the test sample .
