Journal: Applied and Environmental Microbiology

Article Title: Elution Is a Critical Step for Recovering Human Adenovirus 40 from Tap Water and Surface Water by Cross-Flow Ultrafiltration

doi: 10.1128/aem.00870-16

Figure Lengend Snippet: Figure 4 shows XDLVO energy profiles of virion-virion inter- facial interactions at different pH values. For all pH values except 7.6, the calculations were performed for HAdV in 1 mM NaCl. For pH 7.6, size and -potential values used in XDLVO calculations were for virions in the recommended storage buffer (1 mM EDTA plus 10 mM Tris). For pH values of 5.8, the height of the energy barrier increases with pH, with the sole exception of pH 7.6. The deviation from the trend is due to the different background solu- tion (10 mM Tris plus 1 mM EDTA instead of 1 mM NaCl) (see “Size, -potential, and surface charge density of HAdV 40”). The negligible aggregation of virions for pH values of 5.8 is due to the high energy barrier (24.5 kT to 52.6 kT). At pH 4.7, where the energy barrier is 8.0 kT, significant aggregation occurs. At pH 4.0 and pH 4.3, the energy barrier decreases to below 1.2 kT, leading to further aggregation. Due to the high positive -potential (29.4 mV) at pH 2.8, the energy barrier is 20.7 kT and the virion sus- pension is stable. XDLVO energies of virion-membrane interfacial interac- tions in membrane feed solutions made with DI water and tap water. XDLVO calculations for virion-membrane interactions in DI water were performed for an ionic strength of 0.2 mM; this is the approximate ionic strength determined from conductivity measurements of DI water spiked with HAdV 40 stock. However, the streaming potential of the membrane could be measured only with 1 mM NaCl electrolytes, so this value was used to approxi- mate the membrane charge in the HAdV-spiked DI water. The approximation is reasonable because the electrophoretic mobili- ties of virions in DI water (1.65 0.19 m · S1 · V1 · cm at pH 5.8) and in 1 mM NaCl solution (1.72 0.48 m · S1 · V1 · cm at pH 5.8) were not statistically different.

Article Snippet: All samples were characterized in terms of pH (Orion 3-Star Plus meter; Thermo Electron Corp., Waltham, MA), conductivity (Orion 550 conductivity meter; Thermo Electron Corp., Waltham, MA), total organic carbon (TOC) content, and concentrations of key cations.

Techniques: Membrane