ABSTRACT
Metagenomics is the culture-independent analysis of a mixture of microbial genomes using an approach based either on expression or on sequencing. Soil is probably the most challenging of all natural environments for microbiologists, with respect to the microbial community size and the diversity of species present. Soil is considered as a complex environment, which appears to be a major reservoir of microbial diversity resulting from multiple interacting parameters, including pH, water content, soil structure, climate variations and biotic activity. Many culturable microorganisms such as bacteria, yeast and fungi are known to secret important metabolites. As a form of sequence-based screening, shotgun sequencing of metagenomic libraries has recently provided vast amount of data, including phylogenetic relationships, millions of novel genes, and deduced metabolic pathways of unculturable bacteria. Metagenomics methodology has been developed as an effective tool for the discovery of new natural products and microbial functions.
