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

This paper examines the recovery of the enteric adenovirus human adenovirus 40 (HAdV 40) by cross-flow ultrafiltration and interprets recovery values in terms of physicochemical interactions of virions during sample concentration. Prior to ultrafiltration, membranes were either blocked by exposure to calf serum (CS) or coated with a polyelectrolyte multilayer (PEM). HAdV 40 is a hydrophobic virus with a point of zero charge between pH 4.0 and pH 4.3. In accordance with predictions from the extended Derjaguin-Landau-Verwey-Overbeek theory, the preelution recovery of HAdV (rpre) from deionized water was higher with PEMcoated membranes (rprePEM=74.8%±9.7%) than with CS-blocked membranes (rpreCS =54.1%±6.2%). With either membrane type, the total virion recovery after elution (rpost) was high for both deionized water (rpostPEM=99.5%±6.6% and rpost CS =98.8%± 7.7%) and tap water (rpostPEM=89%±15% and rpost CS =93.7%±6.9%). The nearly 100% recoveries suggest that the polyanion (sodium polyphosphate) and surfactant (Tween 80) in the eluent disrupt electrostatic and hydrophobic interactions between the virion and the membrane. Addition of EDTA to the eluent greatly improved the elution efficacy (rpostCS =88.6%±4.3% and rpostPEM=87.0%±6.9%) with surface water, even when the organic carbon concentration in the water was high (9.4±0.1 mg/liter). EDTA likely disrupts cation bridging between virions and particles in the feed water matrix or the fouling layer on the membrane surface. For complex water matrices, the eluent composition is the most important factor for achieving high virion recovery. [ABSTRACT FROM AUTHOR]