Metagenomic strategies for the discovery of novel enzymes with biotechnological application from marine ecosystems

As a consequence of its geochemical and geophysical variability, the marine environment, which is dominated by microorganisms and their viruses, also possesses the greatest diversity of biological life on the planet. The habitats of these microbes range from the harshest of environments in the deep ocean to intimate symbiotic associations with other marine organisms. This ecological diversity leads, in turn, to metabolic diversity and it is now accepted that marine microbes contain a vast reservoir of novel enzymes and metabolites that can be of benefit to society. The challenge is in accessing, exploring, and ultimately exploiting this potential reservoir. A major obstacle to date has been the limited capacity to culture marine microbes but genomic and metagenomic technologies now offer promising new strategies for marine biodiscovery. In this chapter, the different sequence and function-based approaches that can be taken are described and assessed. There have been some modest successes in identifying new enzymes but significant hurdles remain. This is, however, a field in its infancy and one which is moving rapidly. It is likely, however, that on-going and future development of new methodologies for screening and expressing marine bacterial genes is likely to yield many new enzymes with novel properties.