Application of brewery waste-derived nitrocellulose membranes to the concentration of SARS-CoV-2 in wastewater

Wastewater-based epidemiology (WBE) has proven to be a viable approach for providing impartial data on coronavirus disease 2019 (COVID-19) in the community and is considered more economical than clinical tests. WBE applications for COVID-19 require rapid and accurate methods to detect the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater. In this study, an adsorption-based concentration method was tested using a nitrocellulose filter made from brewery waste to determine its applicability for the detection of SARS-CoV-2 in wastewater. To recover viruses attached to the membrane filter, several elution methods were investigated to determine the most effective method. The results revealed that almost all tested nitrocellulose filters (Nitrocellulose-A to -E) yielded an adsorption ratio of >90%. The Nitrocellulose-D filter was chosen as the membrane filter for adsorption because of its rapid filtration time compared with other membrane filters. Furthermore, using the Nitrocellulose-D filter, direct extraction yielded the highest sensitivity for SARS-CoV-2 RNA detection compared with other elution methods. The performance of the adsorption–extraction (AE) method using the Nitrocellulose-D filter was compared with that of the polyethylene glycol (PEG) precipitation method, and its applicability was demonstrated by detecting SARS-CoV-2 RNA in 14 (93%) of 15 wastewater samples, although the SARS-CoV-2 RNA concentrations recovered by the AE method were lower than those of the PEG precipitation method. Further research is needed to evaluate the applicability of the developed method to other viruses for the implementation of WBE in COVID-19 era.