Cellulose, a polysaccharide composed of glucose monomers linked by β-1,4-glycosidic bonds, is the most abundant organic polymer on Earth. Found predominantly in the cell walls of plants, it provides structural rigidity, enabling trees to reach great heights and leaves to maintain their shape. Cotton, the purest natural source of cellulose, contains up to 90% of this polymer, while wood typically consists of 40-50% cellulose, accompanied by lignin and hemicellulose. Algae and certain bacteria also produce cellulose, expanding its natural distribution.

The extraction of cellulose involves separating it from other plant components. In the pulp and paper industry, wood chips undergo chemical pulping (using sulfates or sulfites) or mechanical grinding to remove lignin and isolate cellulose fibers. For high-purity applications, such as pharmaceutical and food-grade products, additional purification steps like bleaching and enzymatic treatment are employed. Nanocellulose, derived from cellulose through acid hydrolysis or mechanical fibrillation, has emerged as a high-value material due to its unique properties at the nanoscale.

Cellulose’s versatility drives its extensive use across industries. In paper manufacturing, cellulose fibers are the primary raw material, providing strength and flexibility to paper products. In the textile industry, cotton cellulose is spun into yarns and woven into fabrics, prized for their breathability and comfort. In food applications, cellulose serves as a dietary fiber, promoting digestive health, and functions as a thickener, stabilizer, or emulsifier in products like ice cream and salad dressings.