Lobster shell shows great healing, bio-stimulant properties
SCIENTISTS from the University of Havana have used lobster waste to generate chitin and chitosan, two key compounds in biomedicine and agriculture.
They used these compounds to produce surgical materials with great healing and antiseptic properties as well as to enhance growth speed and germination in seeds. Research results have been published in international research journals such as Macromol, Food Hydrocolloids, Journal of Applied Polymer Science or Polymer Bulletin.
Chitin is a polymer very common in nature as part of animals' and plants' physical structures. Only cellulose is more abundant than chitin, which makes this compound a highly important renewable resource that can easily be found in arthropods, insects, arachnids, molluscs, fungus and algae.
The fishing industry in Cuba generates great amounts of lobster waste, "a pollutant rich in proteins and chitin", states Prof. Carlos Andr�s Peniche Covas, head of the Biopolymers Research Group, from the Biomaterials Centre of the University of Havana. This group is doing research into chitin and chitosan extraction from such waste, in collaboration with the Spanish Centre for Scientific Research (CSIC), the Complutense University in Madrid (Spain) and the Mexican Research Centre for Food and Development.
Peniche points out that "this work allows for the first accurate and comprehensive results of a university study on chitin and chitosan.
The study starts at the extraction of these compounds from polluting waste of the Cuban fishing industry and it goes on to cover these products' characterisation through traditional techniques and some more innovative ones, the study of their properties, the development of new by-products and the testing of their practical applications in areas useful for this Caribbean country, such as agriculture and biomedicine."
These researchers' work has led to the development of a procedure to obtain surgical materials with great healing and antiseptic properties. "This procedure involves using chitosan to cover surgical threads and lint, into which antibiotics are injected.
By doing this, we obtain medical materials with both antimicrobial and healing properties and, as they are covered in a natural polymer, with a higher degree of biocompatibility." Research shows that such properties remained unmodified after sterilisation.
Two new types of surgical thread were produced in collaboration with the Cuban Superior Institute of Military Medicine "Dr. Luis D�az Soto": Agasut-Q, covered with chitosan (healing properties) and Agasut-QE, covered with chitosan and streptomycin (healing and antimicrobial properties). After pre-clinical and clinical trials were approved, both surgical thread types were introduced and successfully used in several Cuban hospitals.
The study, however, was not restricted to biomedicine. In co-operation with the Cuban National Centre for Agricultural and Livestock Health (CENSA), this group worked in "seed coating to boost farming yields as well as in encapsulation of somatic embryos to design artificial seeds".
In trials, tomato seeds of variety 1-17(140) were coated with chitosan. Under laboratory conditions, treated seeds showed significantly higher growth speed and percentage of successful germination when compared to non-treated seeds.
In Peniche's words, the research group concluded that "chitosan works as a bio-stimulant in tomato seed treatment by producing better seed germination and greater plant height, stem thickness and dry mass about a week earlier than usual".
Chitosan proved to be a natural polymer with great film-generating capacity, apart from other highly interesting properties: chitosan does not produce polluting substances, it is non-toxic and bio-compatible.