Cellulóza

Cellulóza (cellulose) is a natural polymer that forms the primary structural component of plant cell walls. It is the most abundant organic polymer on Earth, accounting for a significant portion of terrestrial biomass. The molecule is a linear homopolysaccharide composed of D-glucose units linked by β-1,4-glycosidic bonds, creating long, unbranched chains that can bundle into crystalline microfibrils. These microfibrils interact through hydrogen bonds and van der Waals forces, giving plant tissues high tensile strength and rigidity while remaining chemically inert to many reagents.

In plants, cellulose is synthesized at the plasma membrane by cellulose synthase enzymes, using UDP-glucose as the substrate. The synthesized chains aggregate into microfibrils that are embedded in a matrix of other polymers such as hemicelluloses and lignin. Cellulóza is insoluble in water and resistant to many chemical reagents. Humans cannot digest cellulose due to the lack of cellulase enzymes, but some ruminant animals and certain microbes can hydrolyze it.

Industrially, cellulose is obtained from wood pulp, cotton, and other plant sources. It has wide applications: paper and textiles (cotton and regenerated fibers such as viscose rayon), regenerated cellulose films (cellophane), and cellulose esters and ethers used as plastics, thickeners, and pharmaceutical excipients. It also serves as dietary fiber in foods. Environmental and economic considerations include renewability, biodegradability, and the potential for sustainable production of bio-based materials.