Microbial hosts as a promising platform for polyphenol production

Plants synthesize a variety of different secondary metabolites, such as polyphenols, terpenoids, alkaloids, etc., with pharmaceutical and nutraceutical importance. Polyphenols have shown numerous health benefits with rare side effects. However, the extraction of these compounds from natural sources cannot meet the increasing consumer demand for natural products, and its purification is often difficult, making the overall process too expensive. In contrast, microbial production of polyphenols is a powerful alternative to produce natural products in large amounts, in an environmentally sustainable way. Nevertheless, plant-derived polyphenols are not naturally produced by microorganisms and therefore require the integration of the heterologous pathway from plants through genetic engineering techniques. In the present chapter, the recent advances in microbial production of plant-derived polyphenols, emphasizing on flavonoids, anthocyanins, curcuminoids, and stilbenes, have been summarized. In addition, different strategies used to increase the product yield, and the production processes are also highlighted.We would like to thank the European Union Framework Program 7 “BacHBerry” (www.bachberry.eu), Project No. FP7- 613793 for financial support, the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/ BIO/04469 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684), and BiotecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020–Programa Operacional Regional do Norte.