Progress in bioextraction processes of chitin from crustacean biowastes

The most common methods for the recovery of chitin from crustacean shells are chemical procedures using strong acids and bases. The chemical demineralization and deproteinization processes have several drawbacks such as depolymerization, anomerization, and deacetylation. Moreover, chemical treatments are hazardous, energy consuming, and environmentally unfriendly. As an alternative to chemical processes for extracting chitin, fermentation processes using microorganisms or proteolytic enzymes have been studied for decades for various crustacean shells. Bioextraction of chitin is emerging as a green and eco-friendly process, thus overcoming some of the shortcomings of chemical extraction. Microorganism-mediated fermentation processes are desirable due to easy handling, simplicity, controllability through optimization of process parameters, ambient temperature, and less environmental impact. The main drawbacks of the biotechnological process are the lower yield and quality of the products and thus a higher cost than the chemical processes. We briefly discuss the critical issues encountered in biotechnological processes for chitin recovery from crustacean shells, together with compiling the most advanced findings during the last decades.