ABSTRACT
Endophytic microorganisms are an important source of bioactive secondary metabolites with enormous potential for the discovery of new molecules for drug discovery, industrial use and agricultural applications. Secondary metabolites display enormous chemical complexity and diversity produced by a few common biosynthetic pathways. Some of the classes of secondary metabolites mainly include polyketides, non-ribosomal peptides, alkaloids, flavonoids, steroids, terpenes, and indole terpenes. Polyketides (PKs) are a group of natural secondary metabolites which have been regarded as one of the richest “drug gold mine” groups since many of them are used as therapeutic drugs. PKs are extremely diverse in both structure and biological activity and are synthesized with the help of enzymes called polyketide synthase (PKS). In past few decades, investigations have been made to understand the biosynthesis of these polyketides and, consequently, to manipulate the genes encoding the polyketide synthases (PKSs) for the production of PK compounds with novel structures. Determining the genetic potential of endophytes for the synthesis of polyketides is a very important tool for estimating their biosynthetic proficiency. It also provides important information about the ecological role of fungal polyketide metabolites. In this chapter, we review the diverse classes of polyketides, their biosynthesis and 128various approaches for engineering the biosynthetic pathways for increasing the metabolite production.
