The potential of biomass-derived bio-liquid to prevent the spread of SARS-CoV-2 from waste and its production-based life cycle assessment.

COVID-19 pandemic caused a significant increase in medical and infected domestic waste, greatly increasing risk of human infected with SARS-CoV-2. Therefore, it is critical to prevent the spread of SARS-CoV-2 from solid waste to humans. Current commercial disinfectants present a high carbon footprint issue. Hence, we prepared a renewable wheat straw-based bio-liquid that can damage SARS-CoV-2 RNA and protein. The wet thermochemical extraction (WTE) bio-liquid, with total organic carbon concentration exceeding 1892 mg/L, could effectively damage the virus. However, dry thermochemical extraction (DTE) samples were not efficient due to their low content of effective compounds. The life cycle assessment showed that WTE bio-liquid production implies lower energy and environmental negative impacts than DTE. Moreover, the process by-product, char, can simultaneously reduce 3.1 million tonnes of global CO2 emissions while used as coal substitute. Yield of bio-liquid extremely exceed commercial disinfectant with just 1 % wheat straw utilisation, which meet the demand of processing solid waste. Further, their costs are significantly lower than commercial disinfectants, which are suitable for developing countries. Therefore, the antiviral bio-liquid produced from agricultural straw can be a new way to meet the needs of preventing the spread of SARS-CoV-2 and resume the sustainable development of society.

Effectiveness of Disinfectants Suitable for Inactivating SARS-CoV-2 at Cold-Chain Temperature.

To prevent the spread of SARS-CoV-2 in cold-chain transportation in China, we developed specific cryogenic disinfectants. Carrier tests were performed against SARS-CoV-2 at - 20 °C for the four cryogenic disinfectants developed and qRT-PCR was used to test the virus RNA. Peracetic acid, chlorine disinfectants (two different concentrations), and quaternary ammonium disinfectant with their antifreeze can all inactivate SARS-CoV-2 in 5 min at - 20 °C. However, after 2-3 h of exposure, only chlorine disinfectant could destroy SARS-CoV-2 RNA. The viruses treated with peracetic acid and quaternary disinfectants showed positive Ct values even after 3 h detected with qRT-PCR. The conclusion was that the cold-chain disinfectants we tested could inactivate SARS-CoV-2 quickly and effectively, but only chlorine disinfectants could destroy nucleic acids in 3 h. Our study also illustrated that using qRT-PCR detection of viral nucleic acids to assess disinfection was inappropriate.

Photo-catalyzed TiO2 inactivates pathogenic viruses by attacking viral genome.

Previous observations have been reported that viruses were inactivated using strong irradiation. Here, new evidence was disclosed by studying the effects of nanosized TiO2 on viral pathogens under a low irradiation condition (0.4 mW/cm2 at UVA band) that mimics the field setting. We showed that photo-activated TiO2 efficiently inhibits hepatitis C virus infection, and weak indoor light with intensity of 0.6 mW/cm2 at broad-spectrum wavelength and around 0.15 mW/cm2 of UVA band also lead to partial inhibition. Mechanistic studies demonstrated that hydroxyl radicals produced by photo-activated TiO2 do not destroy virion structure and contents, but attack viral RNA genome, thus inactivating the virus. Furthermore, we showed that photo-activated TiO2 inactivates a broad range of human viral pathogens, including SARS-CoV-2, a novel coronavirus responsible for the ongoing COVID-19 pandemic. In conclusion, we showed that photo-catalyzed nanosized TiO2 inactivates pathogenic viruses, paving a way to its field application in control of viral infectious diseases.