The recycle and reutilization of food wastes is a promising alternative for supporting and facilitating circular economy. However, engineering industrially relevant model organisms to use food wastes as their sole carbon source has remained an outstanding challenge so far. Here, we reprogrammed Escherichia coli metabolism using modular pathway engineering followed by laboratory adaptive evolution to establish a strain that can efficiently utilize waste cooking oil (WCO) as the sole carbon source to produce monomers of bioplastics, namely, medium-chain α,ω-dicarboxylic acids (MCDCAs). First, the biosynthetic pathway of MCDCAs was designed and rewired by modifying the β-oxidation pathway and introducing an ω-oxidation pathway. Then, metabolic engineering and laboratory adaptive evolution were applied for improving the pathway efficiency of fatty acids utilization. Finally, the engineered strain E. coli AA0306 was able to produce 15.26 g/L MCDCAs with WCO as the sole carbon source. This study provides an economically attractive strategy for biomanufacturing bioplastics from food wastes, which has a great potentiality to be developed as a wide range of enabling biotechnologies for achieving green revolution.

中文翻译：

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重编程大肠杆菌代谢以利用废弃食用油合成生物塑料

食物垃圾的回收和再利用是支持和促进循环经济的一种有前途的替代方案。然而，迄今为止，设计工业相关模式生物以使用食物垃圾作为其唯一碳源仍然是一个突出的挑战。在这里，我们重新编程了大肠杆菌使用模块化途径工程进行代谢，然后进行实验室适应性进化，以建立可以有效利用废弃食用油（WCO）作为唯一碳源生产生物塑料单体的菌株，即中链α，ω-二羧酸（MCDCAs）。首先，通过修改 β-氧化途径和引入 ω-氧化途径，设计并重新连接了 MCDCAs 的生物合成途径。然后，应用代谢工程和实验室适应性进化来提高脂肪酸利用的途径效率。最后，工程菌株大肠杆菌AA0306 能够以 WCO 作为唯一碳源生产 15.26 g/L MCDCAs。这项研究为从食物垃圾中生物制造生物塑料提供了一种具有经济吸引力的策略，该策略具有巨大的潜力，可以作为实现绿色革命的多种使能生物技术进行开发。