Screening of New Microorganisms and Their Useful Genes: From Traditional Methods to Metagenomics

Metagenomics is a discipline that enables the genomic study of unculturaled microorganisms. Microorganisms constitute two third of the Earth’s biological diversity. In many environments, 99% of the microorganisms cannot be cultured by standard techniques. Culture-independent methods are required to study the genetic diversity, population structure and ecological roles of the majority of organisms. Metagenomics is the genomic analysis of microorganisms by direct extraction and cloning of DNA from their natural environment. The screening methods have been designed to select specific genes within metagenomic libraries to detect novel biocatalysts as well as bioactive molecules. To study the complete biological diversity and genes, various vectors or bacterial artificial chromosomes, bioinformatics tools and databases are being developed. To understand the biology of uncultured microbes including bacteria, archaea and viruses the various methodologies and tools are reviewed through metagenomic analysis, Also the application of metagenomic studies in medical and nutrition sciences, antibiotics and pharmaceuticals production, and biotechnology are summerized.