Natural polymers: Renewable raw materials and biotechnological products

Well-known and widespread natural polymers such as cellulose, hemicellulose, lignin, chitin, starch, inulin and proteins, are reserve and building material in plant cells. The share of those polymers in agricultural products (cereals, legumes, tuber) and waste material (straw, maize stalks, husk, leaves etc.) is very high. The complex structure of plant tissue and polymer molecules themselves, requires adequate pretreatment (mechanical, thermal and chemical processes) before separation from above mentioned raw materials. After that step they can be biologically degraded to simple or complex building units (monomers, dimers etc). It is the base of their biotechnological processing into very valuable products (such as starch modifiers, liquid sugars, modified proteins regarding their fusibility, taste, smell, allergic characteristics etc.). Enzymatic preparations for hydrolysis of renewable raw materials are nowadays numerous and efficacious, and their industrial application is much more competitive. Biolo gical polymers that are less known and less extended in nature are specific polysaccharides (hyaluronic acid, xanthans, dextrans, glucans, mannanes, fructosanes, pullulans, gellans), specific proteins, polypeptides and peptides (interferons, insulin, somatostatine, growth hormone, plasminogen activator, factor VII, factor VIII and other enzymes), biodegradable esters (PHBV, PLA, glycol esters), biological lubricants, biotensides etc. Those polymers can be accumulated in the cells of selected microorganisms, or can be excreted into the environment of microorganisms or they can be a result of specific enzyme action on suitable natural substrates. The production of adequate biological molecules is a big challenge for research in modern biotechnology. Their speciality as well as the opportunity of changing their structure makes them in favour of medical appliances production, production of new biological active substances and new drugs. The aim of this work is to draw our attention to: - the wide variety of natur al polymers, - the capability of processing the large-scale polymers to different products (basic chemicals, food, fodder); - achievements and research directions to obtain and to apply specific biopolymers as fine and expensive products (fine chemicals, additives, drugs etc.); - economic aspects of biotechnological processing and production of specific ones.