Wide Host-Range Cloning for Functional Metagenomics

We describe how wide host-range cloning vectors can lead to more flexible and effective procedures to isolate novel genes by screening metagenomic libraries in a range of bacterial hosts, not just the conventionally used Escherichia coli . We give examples of various wide host-range plasmid, cosmid, and BAC cloning vectors and the types of genes and activities that have been successfully obtained to date. We present a detailed protocol that involves the construction and screening of a metagenomic library comprising fragments of bacterial DNA, obtained from a wastewater treatment plant and cloned in a wide host-range cosmid. We also consider future prospects and how techniques and tools can be improved.