A synthetic platform for the cascade synthesis of rare sugars using Escherichia coli whole cells was established. In the cascade, the donor substrate dihydroxyacetone phosphate (DHAP) was generated from glycerol by glycerol kinase (GK) and glycerol phosphate oxidase (GPO). The acceptor d-glyceraldehyde was directly produced from glycerol by an alditol oxidase. Then, the aldol reaction between DHAP and d-glyceraldehyde was performed by l-rhamnulose-1-phosphate aldolase (RhaD) to generate the corresponding sugar-1-phosphate. Finally, the phosphate group was removed by fructose-1-phosphatase (YqaB) to obtain the rare sugars d-sorbose and d-psicose. To accomplish this goal, the alditol oxidase from Streptomyces coelicolor (AldOS.coe) was expressed in E. coli and the purified AldOS.coe was characterized. Furthermore, a recombinant E. coli strain overexpressing six enzymes including AldOS.coe was constructed. Under the optimized conditions, it produced 7.9 g/L of d-sorbose and d-psicose with a total conversion rate of 17.7% from glycerol. This study provides a useful and cost-effective method for the synthesis of rare sugars.

中文翻译：

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Coelicolor链霉菌醛糖醇氧化酶的表征及其在稀有糖生产中的应用。

建立了利用大肠杆菌全细胞级联合成稀有糖的合成平台。在级联反应中，甘油甘油激酶（GK）和甘油磷酸氧化酶（GPO）由甘油生成供体底物磷酸二羟基丙酮磷酸酯（DHAP）。受体d-甘油醛是通过糖醇氧化酶由甘油直接产生的。然后，通过1-鼠李糖-1-磷酸醛缩酶（RhaD）进行DHAP和d-甘油醛之间的醛醇缩合反应，生成相应的糖-1-磷酸酯。最后，果糖-1-磷酸酶（YqaB）去除了磷酸基团，得到了稀有的糖d-山梨糖和d-癸糖。为了实现这个目标，来自大肠杆菌的链霉菌的醛糖醇氧化酶（AldOS.coe）在大肠杆菌中表达，并对纯化的AldOS.coe进行了表征。此外，重组大肠杆菌。构建了过量表达包括AldOS.coe在内的6种酶的大肠杆菌菌株。在优化的条件下，它生产了7.9 g / L的d-山梨糖和d-癸糖，甘油的总转化率为17.7％。这项研究为合成稀有糖提供了一种有用且具有成本效益的方法。