ABSTRACT
Developments in the fields of metabolic engineering, systems biology, and synthetic biology have enabled the engineering of microbial cells to produce natural and the non-natural biomolecules with special biological activities. Many of these compounds are natural products isolated originally in tiny amounts from plants, animal tissues, or microorganisms. Flavonoids are secondary metabolites widespread in the plant kingdom. These colorful natural products are low-molecular-weight molecules composed of a simple 15 carbon backbone. The flavonoids biosynthetic pathway in plants is well studied and was found to have a common core unit, chalcone, from the phenylpropanoid pathway. Other researchers have made use of modular metabolic engineering to enhance flavonoid production in microbial hosts. By this approach, the biosynthetic pathway is designed as a combination of a few modules, where each of them is composed of a subset of all the metabolic reactions.
