Metabolic Engineering and Synthetic Biology-Driven Strategies to Harness Microbial Production of Adipic Acid: Current Status and Future Direction

Adipic acid (AA) is an important dicarboxylic acid that serves as a precursor in the synthesis of nylon-6,6. Given the increasing market demand for AA and the environmental concerns associated with its conventional production, the development of sustainable biosynthetic techniques for AA production has become a key research focus in both industry and academia. However, industrially viable technologies for AA biosynthesis remain constrained by several challenges, particularly incomplete raw material utilization, low strain conversion efficiency, a complex fermentation process, and high costs of downstream separation. To overcome these barriers, this review presents the current state of AA biosynthesis, critically discussing biosynthetic pathways and advanced metabolic engineering strategies and tools for constructing cell factories with high conversion efficiency. The basic principles relevant to improving the fermentation process and downstream separation technologies are also comprehensively reviewed. Key challenges and knowledge gaps are identified, providing insights to guide future research toward commercially viable biobased AA production.