Biodegradable Polymers Based on Proteins and Carbohydrates

Abstract

Biodegradable polymers have become an import focus of interest in recent years. They include polymers manufactured from feedstocks originating either from non-renewable petroleum resources or from renewable biological resources. This review presents a general overview of biodegradable polymers, with a special emphasis on the polymers based on proteins and carbohydrates. Most biodegradable polymers (e.g., starch, chitin, cellulose, collagen and other polypeptides) have been synthesised or are formed in the natural environment during the growth cycles of organisms. These complex forms of carbohydrate consisting of glycosidic bonds are usually one of the major constituents of animal and vegetable exoskeletons (cellulose, carrageenan, chitin). Scientists have already identified certain microorganisms and enzymes that can degrade such polymers. Certain polymers draw attention to their biodegradability property. Bacteria, plants and animals produce this type of polymer, which presents the possibility for very momentous renewable resources. Some of the main plant proteins that can be used as potential sources are soy protein, corn protein (zein) and wheat proteins (gluten). Casein, collagen protein or gelatin, and keratin are important animal proteins. Environmental effects and chemical structure are the main factors upon which biodegradability depends. Another feature that depends on these factors is mechanical behaviour. Some other factors that impact mechanical behaviour are: processing parameters, storage, etc.