Biopolymer

Biopolymers are polymeric materials that originate from living organisms or from renewable biological resources. The term encompasses natural polymers produced by biological systems as well as polymers synthesized through biological processes, such as fermentation, using renewable feedstocks. Biopolymers may be biodegradable, but biodegradability is not universal, and some biopolymers can persist in certain environments.

Natural biopolymers include polysaccharides such as cellulose, starch, chitin, alginates, and pectins; proteins such as collagen, gelatin, silk fibroin, and casein; and nucleic acids such as DNA and RNA. Microbial exopolysaccharides like xanthan gum, gellan gum, and pullulan are also categorized as biopolymers. In addition, there are bio-based synthetic polymers produced by microorganisms or enzymatic processes, including poly(lactic acid) (PLA) and polyhydroxyalkanoates (PHA, e.g., polyhydroxybutyrate), as well as starch- and cellulose-derived materials.

Properties and processing of biopolymers depend on their chemical structure, molecular weight, crystallinity, and degree of crosslinking. They can be processed by methods such as solution casting, melt processing, extrusion, electrospinning, and film formation. Many biopolymers exhibit biocompatibility and can be tailored through blending, chemical modification, or composite formation to suit specific applications.

Applications span medicine (tissues engineering scaffolds, sutures, drug delivery), wound care, packaging, and agriculture. Environmental considerations include the potential for reduced fossil resource use and improved end-of-life options in some cases, balanced against factors such as production energy, land use, and the availability of appropriate disposal or recycling pathways.