Deep eutectic solvents (DESs), considered to be “green media”, have recently been employed in multiple applications including biotransformations. Here, a DES was used in the production of isoquercitrin and l-rhamnose from rutin by enzymatic transformation with recombinant α-l-rhamnosidase from Aspergillus niger. A solution synthesized from choline chloride and urea (ChCl-U) performed best in the conversion of rutin among 24 kinds of DESs. When 130 g/L rutin was used as the substrate, the conversion rate was 100% and the productivity of l-rhamnose and isoquercitrin was 208.68 mM/h under optimized conditions in ChCl-U solution, which was 1.12 times higher than that in buffer (186.92 mM/h). The recycling of ChCl-U solution was also investigated by aqueous two-phase system extraction of l-rhamnose, and ChCl-U/K₂HPO₄ was screened as the suitable extraction solvent. When the ChCl-U content was 34%, the extraction efficiency of l-rhamnose was 79.06% with a purity and primary crystallization yield of 96.28 and 66.49%, respectively. After five cycles of ChCl-U solution, the average enzymatic conversion rate of recycling was 95.63% with an average purity of 94.22% of the isoquercitrin prepared. After 10 cycles of reuse, the residual conversion rate was 61.14%. The results indicate that the DES has obvious advantages in biocatalytic processes involving flavonoid conversion.

中文翻译：

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使用深共晶溶剂将芦丁高效酶促转化为异槲皮苷和1-鼠李糖

深共熔溶剂（DES）被认为是“绿色介质”，最近已用于包括生物转化在内的多种应用中。在此，将DES用于通过从黑曲霉中重组α- 1-鼠李糖苷酶的酶促转化，从芦丁生产异槲皮苷和1-鼠李糖。在24种DES中，由氯化胆碱和尿素（ChCl-U）合成的溶液在芦丁的转化中表现最佳。当使用130 g / L芦丁作为底物时，转化率为100％，产率为1在优化条件下，ChCl-U溶液中的鼠李糖和异槲皮苷为208.68 mM / h，比缓冲液（186.92 mM / h）高1.12倍。还通过1-鼠李糖的水两相系统萃取研究了ChCl-U溶液的再循环，并筛选了ChCl-U / K ₂ HPO ₄作为合适的萃取溶剂。当ChCl-U含量为34％时，l的提取效率为鼠李糖为79.06％，纯度和一次结晶产率分别为96.28％和66.49％。经过五次ChCl-U溶液循环后，循环使用的平均酶转化率为95.63％，平均纯度为所制备的异槲皮苷的94.22％。在重复使用10个循环后，残留转化率为61.14％。结果表明，DES在涉及类黄酮转化的生物催化过程中具有明显的优势。