Enrichment of Marine Viruses via Size-Based Filtration and Centrifugal Concentration

Begin with a seawater sample containing free viruses and viruses attached to host microbes.

Take a filtration unit with a large-pore filter membrane and pass the sample through it to retain the microbes while allowing the free viruses to pass through.

Next, take a filtration unit with a small-pore filter membrane and pass the filtrate through it to separate the large viruses while enriching the small viruses in the ultrafiltrate.

Cut out both used filter membranes and store them separately in a small volume of the ultrafiltrate for later analysis.

Load the remaining ultrafiltrate into a centrifugal filtration unit fitted with smaller-pore filter membranes.

During centrifugation, water and small molecules pass through the membrane, while the small viruses are retained. This reduces the volume and enriches the sample.

Place the concentrate cup over the filter, invert the assembly, and centrifuge it to recover the concentrated viral retentate.

Collect the viruses for further analysis.

Filter the water sample through a filter cup assembly, then connect the filter cup to a portable air diaphragm vacuum pump using clear vinyl tubing. Transfer the sample into the filter cup and begin filtration.