Metagenomic technology and genome mining: emerging areas for exploring novel nitrilases

Nitrilase is one of the most important members in the nitrilase superfamily and it is widely used for bioproduction of commodity chemicals and pharmaceutical intermediates as well as bioremediation of nitrile-contaminated wastes. However, its application was hindered by several limitations. Searching for new nitrilases and improving their application performances are the driving force for researchers. Genetic data resources in various databases are quite rich in post-genomic era. Besides, more than 99 % of microbes in the environment are unculturable. Metagenomic technology and genome mining are thus becoming burgeoning areas and provide unprecedented opportunities for searching more useful novel nitrilases due to the abundance of already existing but unexplored gene resources, namely uncharacterized genome information in the database and unculturable microbes in the natural environment. These techniques seem to be innovative and highly efficient. This study reviews the current status and future directions of metagenomics and genome mining in nitrilase exploration. Moreover, it discussed their utilization in coping with the challenges for nitrilase application. In the next several years, with the rapid development of nitrile biocatalysis, these two techniques would be bound to attract increasing attentions and even become a dominant trend for finding more novel nitrilases. Also, this review would provide guidance for exploitation of other commercially important enzymes.