title: Development of a virus concentration method using lanthanum-based chemical flocculation coupled with modified membrane filtration procedures.
abstract: Direct membrane filtration is often used to concentrate viruses in water but it may suffer from severe membrane fouling and clogging. Here, a lanthanum-based flocculation method coupled with modified membrane filtration procedures was developed and evaluated to detect viruses in large volume (40 L) water samples. The lanthanum-based flocculation method could easily reduce the water sample volume by a factor of 40. Additional volume reduction was achieved by a two-step membrane filtration approach. First, selected membrane filters (including 1MDS electropositive filters and nitrocellulose electronegative filters-Millipore HATF filters) were used to reduce water sample volume further and compare their efficiencies in virus recovery. The Mg²⁺-modified HATF membrane performed better on MS2 retention with an average virus recovery of 83.4% (±4.5% [standard deviation]). After HATF membrane filtration and elution, centrifugal ultrafiltration through a 30 kDa cut-off membrane resulted in an overall concentration factor of 20,000. Results from the infectivity assay showed that the MS2 recovery efficiencies from the NanoCeram- and 1MDS-based direct filtration and the lanthanum-based concentration coupled with the modified filtration procedure were 10.1% (±1.0%), 3.3% (±0.1%), and 17.5% (±1.1%), respectively. Results from the PCR analysis showed that the virus recoveries of the lanthanum-based method were 20.6% (±2.9%) and 19.5% (±3.4%) for MS2 and adenovirus, respectively, while no adenovirus could be detected through the NanoCeram- and 1MDS-based direct filtration. The lanthanum-based concentration method coupled with modified membrane filtration procedures is therefore a promising method for detecting waterborne viruses.
authors.affiliation: Department of Civil and Environmental Engineering, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Lela K
authors.initials: LK
authors.lastname: Riley
authors.forename: Mengshi
authors.initials: M
authors.lastname: Lin
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Purdy
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Hu
mesh_terms: D005591:Chemical Fractionation / Q000379:methods*; D005374:Filtration / Q000379:methods*; D005427:Flocculation; D007811:Lanthanum / Q000378:metabolism*; D014773:Virology / Q000379:methods*; D014780:Viruses / Q000302:isolation & purification*; D014871:Water Microbiology
chemical_list: D007811:Lanthanum