Yan Wenlong, Qi Xinhua, Cao Zhibei, Yao Mingdong, Ding Mingzhu, Yuan Yingjin
Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
Frontiers Research Institute for Synthetic Biology, Tianjin University, Tianjin, 300072, China.
Synth Syst Biotechnol. 2024 Apr 11;9(3):531-539. doi: 10.1016/j.synbio.2024.04.006. eCollection 2024 Sep.
There has been extensive research on the biological recycling of PET waste to address the issue of plastic waste pollution, with ethylene glycol (EG) being one of the main components recovered from this process. Therefore, finding ways to convert PET monomer EG into high-value products is crucial for effective PET waste recycling. In this study, we successfully engineered to utilize EG and produce glycolic acid (GA), expecting to facilitate the biological recycling of PET waste. The engineered , able to utilize 10 g/L EG to produce 1.38 g/L GA within 96 h, was initially constructed. Subsequently, strategies based on overexpression of key enzymes and knock-out of the competing pathways are employed to enhance EG utilization along with GA biosynthesis. An engineered , characterized by the highest GA production titer and substrate conversion rate, was obtained. The GA titer increased to 5.1 g/L with a yield of 0.75 g/g EG, which is the highest level in the shake flake experiments. Transcriptional level analysis and metabolomic analysis were then conducted, revealing that overexpression of key enzymes and knock-out of the competing pathways improved the metabolic flow in the EG utilization. The improved metabolic flow also leads to accelerated synthesis and metabolism of amino acids.
为解决塑料垃圾污染问题，人们对聚对苯二甲酸乙二酯（PET）废料的生物循环利用进行了广泛研究，乙二醇（EG）是此过程中回收的主要成分之一。因此，找到将PET单体EG转化为高价值产品的方法对于PET废料的有效回收至关重要。在本研究中，我们成功构建了能够利用EG并生产乙醇酸（GA）的工程菌，期望促进PET废料的生物循环利用。最初构建的工程菌能够在96小时内利用10 g/L的EG生产1.38 g/L的GA。随后，采用基于关键酶过表达和竞争途径敲除的策略来提高EG利用率以及GA生物合成。获得了以最高GA产量滴度和底物转化率为特征的工程菌。GA滴度提高到5.1 g/L，产率为0.75 g/g EG，这是摇瓶实验中的最高水平。然后进行了转录水平分析和代谢组学分析，结果表明关键酶的过表达和竞争途径的敲除改善了EG利用中的代谢流。改善的代谢流还导致氨基酸的合成和代谢加速。
