The potential of terrestrial biodegradable polymers intercepts the interest of industrial application since it represents a low cost source and an environmentallyconscious alternative. The main substrates from which to obtain such biopolymers are cellulose, starch and lignin. This chapter aims to describe the basic chemical structures and the associated reactions that lead to the various biomaterials, some of which are already marketed and others that represent a strong potential in terms of environmental impact and beyond.