Nonreducing terminal chimeric isomaltomegalosaccharide and its integration with azoreductase for the remediation of soil-contaminated lipophilic azo dyes
Nonreducing terminal chimeric isomaltomegalosaccharide and its integration with azoreductase for the remediation of soil-contaminated lipophilic azo dyes
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非还原末端嵌合异麦芽巨糖及其与偶氮还原酶的整合用于修复土壤污染的亲脂性偶氮染料
DOI：
10.1016/j.carbpol.2023.120565
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发表时间：
2023
影响因子：
11.2
通讯作者：
Kimura Atsuo
中科院分区：
文献类型：
--
作者：
Lang Weeranuch;Sirisansaneeyakul Sarote;Tagami Takayoshi;Kang Hye-Jin;Okuyama Masayuki;Sakairi Nobuo;Kimura Atsuo
亲脂性偶氮染料实际上是不溶于水的，并且它们被有机溶剂和表面活性剂溶解对用活细胞和酶的生物处理有害。本研究旨在评估一种新合成的非还原性末端嵌合异麦芽糖（N-IMS）作为四种模拟亲脂性偶氮染料废物的酶促降解的无毒增溶剂的可行性。通过环糊精葡聚糖转移酶的偶联反应，从α-环糊精衍生出一个带有螺旋α-（1 → 4）-糖苷链段的N-异硫氰酸酯（N-IMS）。通过N-IMS的包合络合克服了溶解度问题，平衡常数为1786-242 M−1（甲基黄>乙基红>甲基红>偶氮紫）。圆二色性光谱显示了N-IMS腔中芳香环的轴向排列，而紫外-可见吸收猝灭显示甲基黄的偶氮键被特别诱导。从酸性和中性土壤中的染料解吸是特定的含水有机碱提取。掺入染料的溶解动力学遵循S形模式，促进随后的脱色过程与偶氮还原酶。结果表明，土壤提取后，固体染料溶解与N-IMS辅助和自发地消化偶氮还原酶/葡萄糖脱氢酶（辅因子再生系统）与相应的芳香胺的释放。
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.