UNAM, TESE Create Sustainable Chitosan Extraction

Researchers from UNAM's Facultad de Estudios Superiores (FES) Cuautitlan and Tecnológico de Estudios Superiores de Ecatepec (TESE) have developed a biotechnological method to sustainably extract chitosan from shrimp shells. The project aims to enhance the sustainability and efficiency of shrimp production, as over 70% of its output is discarded as waste.

The project is led by Ana Sixto, Susana Miranda, and Martín Cruz from UNAM-FES, together with María Martínez from TESE. It proposes a sustainable process that uses lactic acid bacteria to obtain chitin and chitosan, reducing shrimp industry waste while adding value to its byproducts. Chitosan can be applied in medicine, agriculture, food production, and cosmetics.

Chitosan is derived from chitin, a natural polymer found in the shells of crustaceans. The process begins with treating shrimp shells in a bioreactor, where bifidobacterium lactis produces proteases, which are proteins that break the bond between proteins and the shrimp shells, removing the protein content. Following this, Lactobacillus delbrueckii generates lactic acid, which eliminates calcium from the shells. Once the protein and calcium have been removed, chitin is obtained. The next stage involves converting chitin into chitosan through deacetylation, using enzymes produced by the fungus Aspergillus niger.

According to researchers, chitosan is water-soluble and biocompatible, making it suitable for use in wound dressings, surgical sutures, and fertilizers. It also serves as a material for cell therapy gels and scaffolds used in tissue engineering, including 3D printing applications, reports Gaceta UNAM.

Mexico is a leading shrimp producer, ranking second in Latin America and eighth globally, with key production hubs in Sinaloa, Sonora, and Tamaulipas. According to the Research Center on Food and Development (CIAD), over 70% of shrimp production’s weight is discarded as waste, which has a significant environmental impact. However, these residues are an important source of valuable compounds like proteins, carotenoids, chitin, polyunsaturated fatty acids, phenolic compounds, and minerals like calcium and phosphorus, among others.

Chitosan Use in Agriculture

The use of chemicals in agriculture has led to negative consequences due to contamination of the air, water, and soil, caused by the widespread use of pesticides. In response to this, various international organizations and countries have advocated for sustainable practices in plant health management. One such initiative is the use of chitosan as an alternative for controlling fungal pathogens. Research has demonstrated chitosan's antifungal properties, its ability to trigger defense mechanisms, and its biocompatibility with other antimicrobial agents. A study on tomatoes has shown its effectiveness in combating Geotrichum candidum, a fungus that can lead to infections in tomatoes, one of Mexico's most important export crops.