Metabolic Engineering of Microorganisms for the Production of Natural Compounds

Natural products have been attracting much interest around the world for their diverse applications, especially in drug and food industries. Plants have been a major source of many different natural products. However, plants are affected by weather and environmental conditions and their successful extraction is rather limited. Chemical synthesis is inefficient due to the complexity of their chemical structures involving enantioselectivity and regioselectivity. For these reasons, an alternative means of overproducing valuable natural products using microorganisms has emerged. In recent years, various metabolic engineering strategies have been developed for the production of natural products by microorganisms. Here, the strategies taken to produce natural products are reviewed. For convenience, natural products are classified into four main categories: terpenoids, phenylpropanoids, polyketides, and alkaloids. For each product category, the strategies for establishing and rewiring the metabolic network for heterologous natural product biosynthesis, systems approaches undertaken to optimize production hosts, and the strategies for fermentation optimization are reviewed. Taken together, metabolic engineering has enabled microorganisms to serve as a prominent platform for natural compounds production. This article examines both the conventional and novel strategies of metabolic engineering, providing general strategies for complex natural compound production through the development of robust microbial-cell factories.