State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, WuXi, China.
The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, WuXi, China.
Biotechnol J. 2022 Aug;17(8):e2100349. doi: 10.1002/biot.202100349. Epub 2022 May 24.
l-Leucine is an important essential amino acid with multiple industrial applications, whose market requirements cannot be met because of the low productivity.
In this study, a strain of Corynebacterium glutamicum with high l-leucine yield was constructed to enhance its acetyl-CoA supply and glucose utilization. One copy of leuA under the control of a strong promoter was incorporated into the C. glutamicum genome. Then, acetyl-CoA supply was increased by the integration of a terminator in front of gltA and by the heterogeneous overexpression of acetyl-CoA synthetase (ACS) and deacetylase (CobB) derived from Escherichia coli. Next, the transcriptional regulator sugR was deleted to enhance glucose uptake via a phosphotransferase-mediated route. In fed-batch fermentation performed in a 5-L reactor, l-leucine production of 40.11 ± 0.73 g L was achieved under the optimized conditions, with an l-leucine yield and productivity of 0.25 g g glucose and 0.59 g L h , respectively.
These results represent a significant improvement in the l-leucine production of C. glutamicum, indicating that the process possesses high potential for industrial application. These strategies can be also expanded to enable the production of other value-added biochemicals derived from the intermediates of central carbon metabolism.
亮氨酸是一种重要的必需氨基酸，具有多种工业应用，但由于其低生产率，市场需求无法得到满足。
在本研究中，构建了一株产亮氨酸能力高的谷氨酸棒杆菌，以提高其乙酰辅酶 A 的供应和葡萄糖的利用。将一个受强启动子控制的 leuA 拷贝整合到谷氨酸棒杆菌基因组中。然后，通过在 gltA 前整合一个终止子，以及异源过表达来自大肠杆菌的乙酰辅酶 A 合成酶（ACS）和脱乙酰酶（CobB），增加乙酰辅酶 A 的供应。接下来，通过敲除转录调节因子 sugR，通过磷酸转移酶介导的途径增强葡萄糖摄取。在 5-L 发酵罐中进行分批补料发酵，在优化条件下，实现了 40.11 ± 0.73 g/L 的亮氨酸产量，亮氨酸的产率和生产强度分别为 0.25 g/g 葡萄糖和 0.59 g/L/h。
这些结果代表了谷氨酸棒杆菌亮氨酸生产的显著提高，表明该工艺具有很高的工业应用潜力。这些策略也可以扩展到其他从中枢碳代谢中间体衍生的增值生化产品的生产。
