Abstract
The following protocol describes the isolation and purification of viruses infecting cyanobacteria using a liquid bioassay approach. Viruses infecting cyanobacteria are also known as cyanophages. This protocol was written specifically for the isolation of cyanophages infecting freshwater cyanobacteria particularly, cyanobacteria that cannot be cultured on solid media. The use of a clonal cyanobacterial culture is recommended for the isolation of viruses. Growth conditions (i.e., media, light cycle and temperature) should be modified based on the host of interest.