Highly efficient and selective biocatalytic production of glucosamine from chitin

Abstract

N-Acetyl glucosamine (GlcNAc) is one of the most abundant biomolecules on Earth and is cheaply available from chitin, a major component of crustaceans.

An Enzymatic N‐Acylation Step Enables the Biocatalytic Synthesis of Unnatural Sialosides

“…In particular, glucosamine derivatives are fundamental building blocks for the synthesis of a range of hexosamines and sialylated glycoconjugates and are used as bioorthogonal chemical reporters for metabolic glycan labeling and engineering, as illustrated in Scheme . Glucosamine ( 2 ) itself is a valuable food additive that can be generated from chitin through chemical or enzymatic depolymerization to 1 and de‐acetylation . Subsequent epimerizations (to generate the galactose and mannose derivatives 4 and 5 , respectively) and further elaboration to sialic acids ( 6 ) and glycoconjugates can also be achieved enzymatically.…”

“…In the absence of any obvious candidate enzymes from the literature, we looked for promiscuous activities of known biocatalysts. We previously described a recombinant chitin de‐N‐acetylase CmCDA that is able to specifically and efficiently deacylate N ‐acylglucosamine derivatives (including GlcNAc), whereas no activity towards other carbohydrates such as chitobiose, ManNAc, or GalNAc was detected …”

https://researchopenworld.com/addition-of-chitin-nanoparticles-improves-polylactic-acid-film-properties/#

“…The biggest effect was found for yellow and magenta transmission, which also lowers transparency of the films, that appear more brown, and opaque. Hydrolysis of chitin (N-acetyl-D-glucosamine; see nano-chitin preparation section) results in a high yield of glucosamine products [22], that are believed to be responsible for the colour change through Maillard reactions, similarly as observed in other work for glucosamine-derived products [23] [24]. It is good to mention that the brown colour is hardly visible in thin (<0.1mm) films, but it does distinguish the films presented here from low density polyethylene, which show near complete transmission of UV [25].…”

An Enzymatic N‐Acylation Step Enables the Biocatalytic Synthesis of Unnatural Sialosides

“…Glucosamine (2) itself is a valuable food additive that can be generated from chitin through chemical or enzymatic depolymerization to 1 and de-acetylation. [4] Subsequent epimerizations (to generate the galactose and mannose derivatives 4 and 5, respectively) and further elaboration to sialic acids (6) and glycoconjugates can also be achieved enzymatically. However, there remains a gap in the enzyme toolkit in that the acylation of glucosamine (2) needs to be performed chemically, requiring the activation of carboxylic acids or stoichiometric coupling agents and protecting strategies.…”

“…We previously described a recombinant chitin de-N-acetylase CmCDA that is able to specifically and efficiently deacylate N-acylglucosamine derivatives (including GlcNAc), whereas no activity towards other carbohydrates such as chitobiose, ManNAc, or GalNAc was detected. [4] As we were curious how CmCDA de-N-acetylates GlcNAc, we reviewed the postulated mechanism of a reported peptidoglycan deacetylase. [9] The relevant catalytic amino acids are conserved in both enzymes, including the His-His-Asp zinc-binding triad coordinating the N-acetyl group, as well as the respective histidine and aspartic acid residues acting as the catalytic acid and base.…”