Chitin biorefinery: A narrative and prophecy of crustacean shell waste sustainable transformation into bioactives and renewable energy

Recent Advances of Chitosan-Based Hydrogels for Skin-Wound Dressings

“…Chitin is a common biopolymer in nature, second only to cellulose polysaccharides, and is mainly found in flora and fauna, together with insects, algae, crustaceans, and the cell walls of fungi [ 31 ]. It is formed by the N-acetylglucosamine molecule, linked by β-1,4-glycosidic bonds ( Figure 2 A) [ 33 , 34 ]. Chitin is limited in its use because it is poorly soluble in water.…”

Strategies to Prepare Chitin and Chitosan-Based Bioactive Structures Aided by Deep Eutectic Solvents: A Review

“…For instance, chitin deacetylases (EC 3.5.1.41, [178][179][180][181]) are enzymes capable of catalyzing the hydrolysis of GlcNAc subunits to convert them into GlcN, while chitooligosacharide deacetylases (EC 3.5.1.105) can perform the same deacetylation on chitosan and chitooligosacharides following different endo-or exo-mechanisms [181]. These enzymes would therefore be the biotechnological option for converting chitin into chitosan, as the first step in a valorization cycle [61] leading to a chitin-based biorefinery [28].…”

“…Among natural biopolymers, chitin stands out as the second most abundant natural polymer on Earth (only after cellulose, the principal component of plant cell walls and the most abundant source of renewable polysaccharides on Earth [26]). It can be found in a plethora of living beings [27], with some notable sources being crustacean shells [28][29][30][31][32], arthropods [33], mollusks [34], insects [35][36][37], and fungi [38]. Chemically, chitin is a linear polysaccharide composed by a repetition of subunits of 2-amino-2-deoxy-D-glucose (N-acetyl-glucosamine, GlcNAc, Figure 1a) connected by (β1→4) glycosidic bonds (Figure 1b,c).…”

“…The resultant rigidity bolstered by these hydrogen bonds, along with the substantial bulk of the acetamide substituent, not only imparts inflexibility to the chains but also restricts rotation along the glycosidic bonds linking the monosaccharides, leading to highly stable chain conformations (Khoushab and Yamabhai, 2010). Chitin present in its primary natural reservoir, namely crustacean shells [28][29][30][31][32], adopts an antiparallel orientation (α- The resultant rigidity bolstered by these hydrogen bonds, along with the substantial bulk of the acetamide substituent, not only imparts inflexibility to the chains but also restricts rotation along the glycosidic bonds linking the monosaccharides, leading to highly stable chain conformations (Khoushab and Yamabhai, 2010). Chitin present in its primary natural reservoir, namely crustacean shells [28][29][30][31][32], adopts an antiparallel orientation (α-chitin), in which not only intramolecular but also intermolecular hydrogen bonding is present (Figure 1d, red color), resulting in an orthorhombic crystal structure [27,43].…”

“…Chitin present in its primary natural reservoir, namely crustacean shells [28][29][30][31][32], adopts an antiparallel orientation (α- The resultant rigidity bolstered by these hydrogen bonds, along with the substantial bulk of the acetamide substituent, not only imparts inflexibility to the chains but also restricts rotation along the glycosidic bonds linking the monosaccharides, leading to highly stable chain conformations (Khoushab and Yamabhai, 2010). Chitin present in its primary natural reservoir, namely crustacean shells [28][29][30][31][32], adopts an antiparallel orientation (α-chitin), in which not only intramolecular but also intermolecular hydrogen bonding is present (Figure 1d, red color), resulting in an orthorhombic crystal structure [27,43]. Conversely, β-chitin (present in squid pens, clams, oyster shells, and bones of cuttlefish, [34]) features a parallel chain alignment, with no interchain bonding, giving rise to a monoclinic crystal symmetry [43] with higher solubilizing properties.…”