Nonreducing terminal chimeric isomaltomegalosaccharide and its integration with azoreductase for the remediation of soil-contaminated lipophilic azo dyes. (1st April 2023)

• Record Type: Journal Article
• Authors: Lang, Weeranuch; Sirisansaneeyakul, Sarote; Tagami, Takayoshi; Kang, Hye-Jin; Okuyama, Masayuki; Sakairi, Nobuo; Kimura, Atsuo
• Is Part Of: Carbohydrate polymers. Volume 305(2023)
• Publication Date: 2023-04-01
• Subjects: Azobenzene dye -- Biological treatment -- Chimeric structure -- Dye-contaminated soil remediation -- Saccharide solubilizer -- Methyl yellow; AV azo violet -- BrAzo azoreductase -- CGTase cyclodextrin glucanotransferase -- α-CD α-cyclodextrin -- CWMA chloroform + water + methanol + acetone immiscible solution -- DP average degree of polymerization -- D2O deuterium oxide -- ER ethyl red -- GDH glucose dehydrogenase -- HPAEC-PAD high-performance anion-exchange chromatography with pulsed amperometric detection -- Kc stability constant -- Ks equilibrium constant -- L-IMS linear isomaltomegalosaccharide -- MR methyl red -- MY methyl yellow -- NAD+ β-Nicotinamide adenine dinucleotide oxidized form -- NADH β-nicotinamide adenine dinucleotide reduced form -- N-IMS nonreducing terminal isomaltomegalosaccharide; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2023.120565
• Languages: English
• ISSNs: 0144-8617

Abstract

Abstract: Lipophilic azo dyes are practically water-insoluble, and their dissolution by organic solvents and surfactants is harmful to biological treatment with living cells and enzymes. This study aimed to evaluate the feasibility of a newly synthesized nonreducing terminal chimeric isomaltomegalosaccharide (N-IMS) as a nontoxic solubilizer of four simulated lipophilic azo dye wastes for enzymatic degradation. N-IMS bearing a helical α-(1 → 4)-glucosidic segment derived from a donor substrate α-cyclodextrin was produced by a coupling reaction of cyclodextrin glucanotransferase. Inclusion complexing by N-IMS overcame the solubility issue with equilibrium constants of 1786–242 M −1 (methyl yellow > ethyl red > methyl red > azo violet). Circular dichroism spectra revealed the axial alignment of the aromatic rings in the N-IMS cavity, while UV–visible absorption quenching revealed that the azo bond of methyl yellow was particularly induced. Desorption of the dyes from acidic and neutral soils was specific to aqueous organic over alkali extraction. The dissolution kinetics of the incorporated dyes followed a sigmoid pattern facilitating the subsequent decolorization process with azoreductase. It was demonstrated that after soil extraction, the solid dyes dissolved with N-IMS assistance and spontaneously digested by coupled azoreductase/glucose dehydrogenase (for a cofactor regeneration system) with the liberation of the corresponding aromatic amine. Graphical abstract: Unlabelled Image