HISTORY OF CHITIN

Chitin discovery

The history of chitin begins in 1799, when English scientist Alexander Hachett reported a fungal material that resisted common chemical treatments. Around 1811, French chemist and pharmacist Henri Braconnot (pictured left) isolated a nitrogen-containing substance from mushrooms and named it fungine. In 1823,  Antoine Odier discovered the same material in insect exoskeletons and renamed it chitin. A couple decades later, in 1843, Jean Louis Lassaigne confirmed that chitin contained nitrogen, distinguishing it from cellulose, and Anselme Payen began investigating the relationship between the two. In 1878, Georg Ledderhose identified glucosamine and acetic acid as building blocks of chitin. In 1929, Albert Hofmann described the structure of chitin in greater detail and in 1946, the complete chemical structure of chitin was finally established.

Etymology

The name chitin comes from the French word chitine, which in turn comes from the Greek word chiton (χιτών, khitṓn), meaning "cloak"  or "tunic." A chiton was a garment worn by both men and women in Ancient Greece and Rome. It was a simple tunic fastened at the shoulders and draped around the body and scientists chose this name because chitin functions as a protective outer covering in many organisms. 

Chitin

Chitin is the second-most abundant natural polymer in the world after cellulose. It is a structural biopolymer found throughout nature and serves a similar structural role to keratin in human hair, skin, and nails. Chemically, its structure is most similar to cellulose, the material that forms plant cell walls. Chitin forms protective structures throughout nature, including:

• Arthropod exoskeletons (including crustacean and insect shells)
• Insect exoskeletons
• Fungal cell walls
• Fish scales 

Chitin is also the most abundant naturally occurring polysaccharide that contains amino sugars. It is found in association with proteins and minerals, such as calcium carbonate. This abundance, combined with the specific chemistry of chitin and its derivative chitosan, make for the impressive array of potential applications. The different sources of chitin differ somewhat in their structure and percentage of chitin content.

Chitosan

Chitosan was  discovered by accident in 1859, when French physiologist Charles Rouget treated chitin with concentrated potassium hydroxide. This process removed acetyl groups from chitin and produced a new substance. Rouget noticed that the new material dissolved in acidic solutions, unlike chitin. 

This new material would later become known as chitosan, when German scientist Felix Hoppe-Seyler officially gave the substance its current name. Chitosan combines the words "chito-", referring to chitin, and "-san", indicating the modified derivative produced through deacetylation.

Chitosan is commercially derived from chitin and is created through a process called deacetylation, which removes chemical groups known as acetyl groups from chitin. This transformation:

• Makes chitosan soluble in acidic solutions (unlike chitin).
• Introduces reactive amino groups, giving chitosan unique biological and functional properties.
• Enables applications in skincare, wound healing, drug delivery, water purification, wine-making, and biotechnology. 

CHEMICAL STRUCTURE

Chitosan's chemical structure can most simply be described as a co-polymer of glucosamine and acetyl-glucosamine. As a natural cationic biopolymer in its dissolved form (pH<5,7) chitosan possesses a positive charge, giving rise to versatile uses based on its anti-microbial, gelling and film-forming properties. Chitosan consist of a family of products, differing in polymer length, chemical sequences and product purities.

MODERN APPLICATIONS

The scientific understanding of chitosan developed over nearly 150 years before widespread commercial use began. In the 1930s, researchers compared chitosan from fungi and crustaceans to develop chitosan fibres. Between the 1930s and '40s, polymers attracted considerable attention, as evidenced by about 50 patents secured during that time. The first monograph on chitin and chitosan was published in 1951, while the 1960s found chitosan being investigated for blood-clotting applications.

Lack of adequate manufacturing facilities and aggressive competition from synthetic polymer producers restricted the commercial development of chitin and its derivatives. Synthetic polymers are artificial, man-made macromolecules, most often derived from petroleum, for example: plastic, nylon and polyester. Revived interest in chitin and its derivatives came in the 1970s, when the need emerged to better utilise shellfish shells. Industrial chitin and chitosan production began in 1971 in Japan.

Toda, chitin and chitosan are used in several countries worldwide in a variety of applications, and dozens of applications of chitin and its derivatives have successfully been introduced to several industries, including medicine, biotechnology, agriculture, water treatment, wine making, and cosmetics. (Global industry analysis since 2004)

As the largest consumer-product chitosan manufacturer in the world, Primex is proud to be the world leader in the sustainable production of this historic and eco-friendly biopolymer – one that has the potential to transform the world by moving the polymer industry in a greener direction.