Solubility of lignin and chitin in ionic liquids and their biomedical applications

Ionic liquids (ILs), are considered as eco-friendly solvents due to their low vapor pressure and non-volatile properties compared to organic solvents and can be employed during processes for the extraction and/or conversion of lignin and chitin to value-added products which can improve the overall economics of the integrated biorefinery concept. However, relatively few studies have investigated their ability to solubilize and modify during solvation of lignin and chitin in terms of crystallinity, molecular weight, etc., with a significant focus on polysaccharides like cellulose and hemicellulose. Similarly, the biomedical applications of lignin and chitin are not recognised so much as compared to polysaccharides. The aim of this review is survey the current literature based on the cutting-edge-knowledge regarding the solubilization of chitin and lignin in various classes of ILs and furthermore, the upgradation of these biopolymers and/or their derivatives for the biomedical applications. Moreover, this review provides a comprehensive summary of the latest progress on the solubilization of integrated biorefinery lignin and chitin with a wide range of ILs using experimental and theoretical studies.