Chitin is the second most abundant bio-polymer after cellulose constituting of β-(1,4)-linked N-acetylglucosamine monomers forming a sturdy resilient scaffold with a chemical formula of (C8H13O5N)n. This precious substance has been previously obtained from sources like crustaceans, fungi, algae, and bacteria. However, it is understudied in the class Insecta. Its structural integrity contributes to the defence mechanism of most invertebrates. On the other hand, its derivative chitosan is the product of de-acetylation of chitin under alkaline conditions. The solubility of chitosan is influenced by the extent of de-acetylation.
When exploring chitin production in insects such as Black soldier fly, the larval stage and the exoskeleton/exuviae (see figure) is utilized.
The production of chitin and chitosan from the insect exuviae first yields the whole skin processed chitin (see figures below). This whole skin powder can be ground to increase the surface area of action during application.
The production of chitin and chitosan from the insect exuviae first yields the whole skin processed chitin (see figures below). This whole skin powder can be ground to increase the surface area of action during application.
This is followed by its volarization into chitosan (de-acetylated chitin derivative).
Applications of chitin and its derivatives
The distinctive properties, including bio-compatibility, biodegradability, and non-toxicity, render chitin and chitosan as highly valuable products in different sectors.
- In the biomedical field, chitosan serves as a noteworthy component in drug delivery systems, leveraging its capability for sustained drug release mechanisms to ensure continuous therapeutic efficacy. In cancer treatment it plays a pivotal role by acting as a vehicle for targeted delivery of drugs to specific sites, enhancing the precision and effectiveness of treatment. Furthermore, chitosan is used in wound healing, serving as a wound dressing material, thus promoting the regeneration of skin epithelial cells and collagen production. Encapsulation of chitosan is also important to improve human health in facilitating weight loss by binding ingested dietary fat and cholesterol. Chitosan is also regarded as a fiber that is valuable in promoting optimal colonic conditions alongside other health-promoting bio-activities.
- Their environmental applications include their use in water treatment processes. Chitin’s absorbent properties make it effective in removing contaminants such as heavy metals, contributing to the purification of water. Chitin-based materials are also employed for pollutant adsorption, particularly in the treatment of industrial pollutants and the adsorption of silver thiosulfate complexes.
- In the agricultural sector, chitin plays a crucial role in enhancing the production of the antimicrobial phytoalexins in plants that act as chemical weapons when attacked by pathogens contributing to sustainable agricultural practices. Additionally, insect-based organic fertilizer containing chitin has proven beyond measure to increase farm yield productivity of several crops. Simultaneously, chitosan contributes to crop growth by fortifying defense mechanisms against pathogens and promoting overall plant health.
- In the food industry, the polymers are utilized in the production of food preservative packaging containers.
- They are also used as nutraceutical agents in animal production.
How is icipe through the INSEFF programme engaged in Chitin and Chitosan Production?
With the recently growing interest in the development of insect farming, the availability of chitin-containing residual streams, particularly the molting exoskeletons (exuviae), is expected to increase in the near future. This will likely contribute to solid wastes being dumped to landfills. It has been observed that chitin emanating from agricultural sectors or nearby, has led to translation and bio-accumulation of pesticides in marine consumers of chitin, raising concerns about the ecological effects of these residues. Rather than the mentioned, chitin plays a pivotal role in agriculture sector that is icipe’s point of entry to improve health and alleviate hunger. Coupled with the increasing global demand for chitin there is an urgent need to exercise circular economy by utilizing reared insects: silkworms, black soldier flies among other insects. This holds high feasibility since insects are the most abundant species on earth crust.
By: Dr. Cynthia M. Mudalungu
Postdoctoral Fellow (Field: Natural Products Chemistry)
Email: cmudalungu@icipe.org
