NOVELTY - Preparation of cellulose-based material involves extracting celluloses from lignocellulosic biomass, treating the extracted cellulose in alkali solution, forming liquid solution, drying, forming powder material, precooling one or more aqueous solvent, dissolving the powder material in precooled aqueous solvent, forming solution (s1), precooling the solution (s1), forming solid product, thawing the solid product, obtaining transparent cellulose solution, coagulating the resultant solution in aqueous solution of sulfuric acid, and forming regenerated cellulose film.    USE - Preparation of cellulose-based material e.g. bio-based material, which is used as functional additive and material for preparing pharmaceutical, cosmetics, foodstuff, building material, varnish, paint, coating compound and polymer (all claimed). The pharmaceutical is useful for providing antibacterial effect against Gram-positive and Gram-negative bacteria.    ADVANTAGE - The method enables economical, simple and environmentally-friendly preparation of cellulose-based material.    DETAILED DESCRIPTION - Preparation of cellulose-based material involves extracting celluloses from lignocellulosic biomass to remove lignin from the lignocellulosic biomass, treating the extracted cellulose in alkali solution at predetermined temperature for predetermined time, forming liquid solution, drying the liquid solution at temperature (t1) for predetermined time, forming powder material, precooling one or more aqueous solvent at temperature (t1), dissolving the powder material in precooled aqueous solvent for predetermined time, forming solution (s1), precooling the solution (s1) at temperature (t2), forming solid product, thawing the solid product at room temperature, obtaining transparent cellulose solution, coagulating the resultant solution in aqueous solution of sulfuric acid, and forming regenerated cellulose film. The aqueous solvent is chosen from mixed aqueous sodium hydroxide solution and urea solution, and/or mixed aqueous lithium hydroxide solution and urea solution. An INDEPENDENT CLAIM is included for bio-based material, which is obtained by preparing metal-graphene oxide nano composite, mixing the metal-graphene oxide nano composite and cellulose solution, forming interaction mixture, coagulating the interaction mixture in non-solvent coagulant, and regenerating highly porous structure of cellulose membrane, or preparing several solid particulate particles by chemical co-precipitation using chemical chosen from ferrous, ferric chloride and alkali hydroxide, dispersing the particles in cellulose solution, forming cellulose solution mixture, coagulating the cellulose solution mixture in aqueous solution of sulfuric acid, and forming several cellulose beads. The regenerated cellulose membrane has antibacterial property.