<p>Antiviral lignin, designated as FR₂₀₀, was produced using acidic microwave glycerolysis of sugarcane bagasse. The lignin strongly inhibited infection by the human norovirus surrogate, feline calicivirus (FCV) without substantial cytotoxicity. The antiviral activity emerged through direct contact of the lignin with the virion. To develop antiviral fibers, cotton was coated with the antiviral lignin AIF₂₀₀, a crude fraction obtained in the process of FR₂₀₀ preparation. Autofluorescence microscope images confirmed successful even coating of the lignin on the cellulose fiber surfaces. ATR FT-IR spectra supported the incorporation of the lignin. The strong anti-FCV activity of the cellulose-lignin assembly was observed by measuring viral titers of the filtrate passing through the lignin-immobilized cotton. The antiviral material developed in this study, totally composed of lignocellulosic biomass, is potentially useful for protecting our health by capturing virions in daily life and livestock environments.</p> Graphical Abstract <p></p>