Metabolic engineering to construct an acetyl-CoA carboxylase bypass malonyl-CoA biosynthesis pathway

洪季嬋Jenny J. Hung 1, Ethan I. Lan 2

1 PhD Degree Program of Biomedical Science & Engineering

 2Department of Biological Science & Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan

Malonyl-CoA is a central metabolic intermediate involved in the synthesis of diverse natural products, including polyketides, flavonoids, and fatty acids, which have high commercial value in the energy and pharmaceutical industries. Recently, several groups have attempted to use microbial cell factories to produce these malonyl-CoA-derived compounds using metabolic engineering strategies, as it has been proposed as a sustainable approach. However, the native malonyl-CoA synthesis enzyme, acetyl-CoA carboxylase (ACCase), is a large and tightly regulated protein complex, making it difficult to control and optimize. In this study, we developed an efficient malonyl-CoA synthetic pathway by overexpressing malonyl-CoA reductase and β-alanine aminotransferase from β-alanine. Furthermore, we integrated this pathway with β-alanine biosynthesis route to achieve de novo synthesis of malonyl-CoA. This pathway successfully increased the titer of flaviolin and phloroglucinol biosynthesis by 1.2-fold and 1.4-fold, respectively. Our study demonstrates a proof of concept for ACCase-independent malonyl-CoA biosynthesis and has the potential to provide an advanced process for increasing the production of malonyl-CoA-derived products.