ABSTRACT
The inhibitor-free nucleic acids thus obtained can be utilized for subsequent analyses such as amplification cloning and sequencing rRNA genes, genotypic fingerprinting techniques, environmental genomics and transcriptomics analyses. Characterization of microbial community structures, composition and shifts by sequencing of rRNA gene clone libraries has been frequently employed for studying bioremediation processes or identifying microbial bio-indicators of anthropogenic pollution. Metagenomics surmounts the major limitations of cultivation dependent studies, as it involves extraction of nucleic acids directly from environmental samples which theoretically embodies the entire set of microbial community genomes present in a given ecosystem. Fosmid libraries from metagenomic DNA fragments recovered from sludge sample revealed extradiol dioxygenases genes using catechol as a substrate, Metagenomics has now become a widespread approach to discover novel biocatalysts or gene products involved in biodegradation of anthropogenic compounds. Metagenomics has enhanced the development of fundamental knowledge on the mechanisms behind the toxicity of and resistance to the herbicide 2,4-dichlorophenoxyacetic acid.
