School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
Biotechnol Lett. 2023 Oct;45(10):1355-1364. doi: 10.1007/s10529-023-03415-6. Epub 2023 Jul 24.
In our previous study, we constructed a one-pot multi-enzyme system for rare ketoses synthesis based on L-rhamnulose-1-phosphate aldolase (RhaD) from accessible glycerol in vitro. To eliminate tedious purification of enzymes, a facile Escherichia coli whole-cell cascade platform was established in this study.
To enhance the conversion rate, the reaction conditions, substrate concentrations and expressions of related enzymes were extensively optimized.
The biosynthetic route for the cascade synthesis of rare ketoses in whole cells was successfully constructed and three rare ketoses including D-allulose, D-sorbose and L-fructose were produced using glycerol and D/L-glyceraldehyde (GA). Under optimized conditions, the conversion rates of rare ketoses were 85.0% and 93.0% using D-GA and L-GA as the receptor, respectively. Furthermore, alditol oxidase (AldO) was introduced to the whole-cell system to generate D-GA from glycerol, and the total production yield of D-sorbose and D-allulose was 8.2 g l only from the sole carbon source glycerol.
This study demonstrates a feasible and cost-efficient method for rare sugars synthesis and can also be applied to the green synthesis of other value-added chemicals from glycerol.
在我们之前的研究中，我们构建了一种基于易得甘油的新型一锅多酶体系，用于合成稀有酮糖。为了避免繁琐的酶纯化过程，本研究建立了一种简便的大肠杆菌全细胞级联平台。
为了提高转化率，我们广泛优化了反应条件、底物浓度和相关酶的表达。
成功构建了稀有酮糖的级联生物合成途径，使用甘油和 D/L-甘油醛（GA）生产三种稀有酮糖，包括 D-阿洛酮糖、D-山梨糖和 L-果酮糖。在优化条件下，使用 D-GA 和 L-GA 作为受体时，稀有酮糖的转化率分别达到 85.0%和 93.0%。此外，向全细胞体系中引入了醛醇氧化酶（AldO），可从甘油生成 D-GA，仅以甘油为唯一碳源，D-山梨糖和 D-阿洛酮糖的总产量达到 8.2 g/L。
本研究为稀有糖的合成提供了一种可行且经济高效的方法，也可应用于从甘油绿色合成其他有价值的化学品。
