1 Biopolymers : State of the Art , New Challenges , and Opportunities

The term “biopolymers” usually describes polymers produced in a natural way by living species. Their molecular backbones are composed of repeating units of saccharides, nucleic acids, or amino acids and sometimes various additional chemical side chains contributing also to their functionalities. If the largest part of biopolymers is extracted from biomass, such as polysaccharides from cellulose and proteins from collagen or milk, biopolymers can also be produced from biomonomers using conventional chemical processes as polylactic acid, or directly in microorganisms or genetically modified organisms, as polyhydroxyalkanoates. The genetic manipulation of microorganisms brings a tremendous potentiality for the biotechnological production of biopolymers with tailored properties quite suitable for high-value medical applications such as tissue engineering and drug delivery. Throughout history, biopolymers have been mainly used by mankind as food, or for making clothing and furniture. Since the industrial time, fossil fuels such as oil are the greatest source in the development and manufacture of almost every commercial product, such as the plastic, which is currently used at a very large scale. But these fuels are not unlimited resources, and environmental concerns over all aspects of using fossil fuels for production and energy must be taken into account. Wemust act in a sustainable manner, whichmeans that the resourcesmust be consumed at a rate such that they can be restored by natural cycles of our planet. Therefore, today, the renewable nature of biopolymers leads them to a renaissance and a new interest. In the last 20 years, this interest in sustainable products has driven the development of new biopolymers from renewable feedstocks. Biopolymers have to compete with polymers derived from fossil fuel not only because of their functional properties but also in terms of cost. In this respect, biopolymers are competitive when the price of oil is high and the price of feedstocks, such as starch from corn, is low.