Hollow Fiber Ultrafiltration to Concentrate Viruses from Environmental Waters

摘要

Current methods for the concentration of viruses from environmental waters use adsorption to microfilters and elution off the membrane as the initial steps to recover viruses. The efficiency of viral recovery by the adsorption/elution process can be affected by water quality, such as pH, salinity, turbidity and target virus. The use of ultrafiltration as a concentration method utilizes size exclusion rather than viral adsorption/elution to concentrate viral particles. In the first set of experiments, we used a large-scale (100L) and a small-scale (～2-3L) 50,000 MWCO polyacrylonitrile hollow fiber ultrafilter system to recover three model viruses in laboratory samples. For each experiment, the initial viral suspension (input), filtered sample (permeate) and final concentrate (retentate) were collected and analyzed by plaque assay to determine viral concentration and recovery efficiency. Each experiment was performed in triplicate using the three-model viruses (bacteriophage PP7 and T1 and poliovirus type 2). Recoveries of 71% (T1), 70% (PP7), and 82% (poliovirus 2) were observed in ground water and 70% (Tl), 86% (PP7) and 69% (poliovirus 2) in surface waters using the large-scale system. Similar recoveries were observed in the small-scale system. Additional experiments concentrated 100L of surface water through a two-step filtration process. Recoveries of ～100% (Tl), 66% (PP7) and 56% (poliovirus 2) were observed. The results from these experiments suggest that viral recoveries of >50% can be achieved for all three model viruses when filtering water from 100L to～200ml.