The soil metagenome--a rich resource for the discovery of novel natural products.

Soil microorganisms have been the most valuable source of natural products, providing industrially important antibiotics and biocatalysts. But, of late, the discovery rate of novel biomolecules using traditional cultivation techniques has been extremely low, as most soil microorganisms cannot be cultured in this way. The development of novel cultivation-dependent and molecular cultivation-independent approaches has paved the way for a new era of product recovery from soil microorganisms. In particular, gene-mining based on the construction and screening of complex libraries derived from the soil metagenome provides opportunities to fully explore and exploit the enormous genetic and metabolic diversity of soil microorganisms. This strategy has already resulted in the isolation of novel biocatalysts and bioactive molecules.