Molecular and biotechnological aspects of secondary metabolites in actinobacteria.

The ability to produce plethora of secondary metabolites and enzymes for pharmaceutical, agricultural and biotechnological applications make actinobacteria one of the most explored microbes among prokaryotes. The secondary metabolites and lytic enzymes of actinobacteria are known for their role in various physiological, cellular and biological processes including environmental sensing, mineral acquisition and recycling, and establishing social communication. In addition, the basic scaffold of secondary metabolties derived from actinobacteria is a source of inspiration for chemists. Recent development in "gene to metabolites" and "metabolites to gene" based omics technologies have played major role in revealing the prevalence of silent gene clusters in the genome of actinobacteria. Moreover, the development in precision-based genome editing tools and use of artificial gene operon for pathway engineering have emerged as a key player in activation of these silent/cryptic gene clusters for novel metabolites at large scale which were previously found to be poorly expressed and difficult to characterize in lab conditions. The access to diverse uncharacterized biosynthetic gene clusters of different types and the leverage of modern gene editing tools for modulated expression of the operons would contribute to novel product discovery and product diversification compared to traditional way of mining metabolites. Here, in review article, we have discussed the taxonomic status, genomic potential of actinobacteria for various secondary metabolites and role of genetic engineering to explore these microbes for human welfare.