Historical Landmarks in the Discovery of Chitin

In 1799, Hatchett decalcified shells of crabs, lobsters, prawns, and crayfish with mineral acids, observing that ``they produced a moderate effervescence and in a short time were found to be soft and plastic of a yellowish color and like a cartilage, which retained the original figure''. Although this is the first mention of calcified chitin in invertebrates, the discovery of chitin is usually attributed to Braconnot in 1811 who discovered it from fungi, and its recognition to Odier in 1823 who obtained a hornlike material after treatment of cockchafer elytra with potassium hydroxide. Chitin first named fongine by Braconnot and then chitine by Odier. Children revealed the nitrogenous nature of chitin in 1824. The history of chitosan, the main derivative of chitin, dates back to 1859 with the work of Rouget. The name of chitosan was, however, introduced in 1894 by Hoppe-Seyler. In 1876, Ledderhose hydrolyzed arthropod chitin and discovered glykosamin, the first derivative of chitin. The main aim of this chapter is to describe the 220 years of the development of chitin. I have roughly divided it into five periods: discovery from 1799 to 1894, a period of confusion and controversy from 1894 to 1930, exploration in 1930-1950, a period of doubt from 1950 to 1970, and finally the period of application from 1970 to the present day. The different periods are illustrated by considering examples of studies that appeared in the literature and in particular those of several great scientists who have left their mark on the history of this polysaccharide. Although this historic review cannot hope to be exhaustive, it does highlight the work of those researchers who have contributed to the development of our knowledge of chitin throughout the 220 years of its history.