Construction of Small-Insert and Large-Insert Metagenomic Libraries.

The vast majority of the Earth's biological diversity are hidden in uncultured and yet uncharacterized microbial genomes. The construction of metagenomic libraries is one cultivation-independent molecular approach to assess this unexplored genetic reservoir. High numbers of novel biocatalysts have been identified by function-based or sequence-based screening of metagenomic libraries derived from various environments. Here, we describe detailed protocols for the construction of metagenomic small-insert and large-insert libraries in plasmids and fosmids, respectively, from environmental DNA.