Preparation of 4-Deoxy-L-erythro-5-hexoseulose Uronic Acid (DEH) and Guluronic Acid Rich Alginate Using a Unique exo-Alginate Lyase from Thalassotalea crassostreae

Abstract

Marine multicellular algae are considered promising crops for the production of sustainable biofuels and commodity chemicals. However, their commercial exploitation is currently limited by a lack of appropriate and efficient enzymes for converting alginate into metabolizable building blocks, such as 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH). Herein, we report the discovery and characterization of a unique exo-alginate lyase from the marine bacterium Thalassotalea crassostreae that possesses excellent catalytic efficiency against poly-β-D-mannuronate (poly M) alginate, with a k of 135.8 s, and a 5-fold lower k of 25 s against poly-α-L-guluronate (poly G alginate). We propose that this preference for poly M is due to a structural feature of the protein's active site. The mode of action and specificity of this enzyme has made it possible to design an effective and environmentally friendly process for the production of DEH and low molecular weight guluronate-enriched alginate.

Purification and Characterization of a Novel Endolytic Alginate Lyase from Microbulbifer sp. SH-1 and Its Agricultural Application

“…Alginate lyases with endolytic activity generally act on glycosidic bonds within the linear polysaccharides chain of alginate, releasing unsaturated alginate oligomers which are dominated by disaccharides, trisaccharides, and tetrasaccharides [40]. Exolyases further depolymerize these oligosaccharides into monosaccharides [5]. The degradation products of alginate and polyM prepared by AlgSH7 mainly consist of oligosaccharides with DP of 2-4, which is similar to other polyM-specific enzymes in the PL7 family, such as AlgA from Bacillus sp.…”

Characterization of a bifunctional alginate lyase as a new member of the polysaccharide lyase family 17 from a marine strain BP-2

“…The results showed that the active site of Alg17B was in the α-helix region of the N -terminus, and the substrate binding site and Zn 2+ ion-binding site were distributed in the β-sheet region of the C -terminus. The alginate lyase, Tc Alg1, is a macromolecular enzyme with exolytic activity, and both its active site and its substrate binding site lie in the α-helix of the N -terminus (Wang et al 2018a), indicating the structural difference between Alg17B and Tc Alg1.…”

Efficient Degradation of Alginate And Preparation of Unsaturated Monosaccharides By A Novel Alginate Lyase And Effects of Domain Truncation On Biochemical Characteristics, Degradation Patterns

“…For example, OalS17(Wang et al, 2014) from Shewanella sp. Kz7 showed the highest activity at 50 o C and pH 6.2, and TcAlg1 from Thalassotalea crassostreae exhibited the maximal activity at 40 o C and pH 7.0(Wang et al, 2018). Moreover, the optimal temperature and pH of Oalv17 were 40 o C and 7.2(Li et al, 2020), respectively.…”