From the problem to the solution: Chitosan valorization cycle.

The problem of fisheries waste has increased in recent years and has become a global problem influenced by various biological, technical, operational and socioeconomic factors. In this context, the use of these residues as raw materials is a proven approach not only to reduce the crisis of unprecedented magnitude facing the oceans, but also to improve the management of marine resources and increase the competitiveness of the fisheries sector. However, the implementation of valorization strategies at the industrial level is being excessively slow, despite this great potential. Chitosan, a biopolymer extracted from shellfish waste, is a clear example of this because although countless chitosan-based products have been described for a wide variety of applications, commercial products are still limited. To address this drawback, it is essential to consolidate a "bluer" chitosan valorization cycle towards sustainability and circular economy. In this perspective we wanted to focus on the cycle of valorization of chitin, which allows to transform a waste product (chitin) into a material suitable for the development of useful products to solve the source of its origin as a waste product and pollutant; chitosan-based membranes for wastewater remediation.