Fishery waste valorisation: Chitin pulping using Ionic Liquids

Abstract

The aim of the work described in this thesis was the valorisation of fishery waste biomass to obtain chitin with a sustainable and green approach using Ionic Liquids (ILs). In particular, attention was focused on the development of an extraction protocol for chitin from Spider Crab (Maja squinado) carapace, with a “waste to wealth” idea to obtain high added-value products. Chitin, in fact, finds various applications in different fields due to its intrinsic biocompatibility and biodegradability, ecological safety, low toxicity and biological activity such as antimicrobial and low immunogenicity. The key step of this work was the improvement of a one-step extraction procedure using ILs as both extracting agents and solvents, in opposition to the traditional chemical extraction which involves two steps using strong and hazardous acids and basis. The one-pot pulping-based method was investigated, using simple, readily-available ILs such as hydroxyl-ammonium acetate, ammonium acetate and ammonium formate. Each extraction was performed in two ways: using the IL as solid salt or synthesizing it in-situ. The study of different reaction parameters, such as temperature, time and IL/crude waste ratio, was performed to optimize the extraction conditions. The pulped-chitin was fully characterized by FT-IR and NMR spectroscopy, XRD, Elemental Analysis (EA), ICP-OES and GPC to define acetylation degree, molecular weight and purity of the products.