title: Recent advances and challenges in the heterologous production of microbial nitrilases for biocatalytic applications.
abstract: The aim of this study is to review the current state of and highlight the challenges in the production of microbial nitrilases as catalysts for the mild hydrolysis of industrially important nitriles. Together with aldoxime dehydratase, the nitrile-hydrolyzing enzymes (nitrilase, nitrile hydratase) are key enzymes in the aldoxime-nitrile pathway which is widely distributed in bacteria and fungi. The availability of nitrilases has grown significantly over the past decade due to the use of metagenomic and database-mining approaches. Databases contain plenty of putative enzymes of this type, whose overproduction may improve the spectrum and the industrial utility of nitrilases. By exploiting this resource, the number of experimentally verified nitrilases has recently increased to several hundred. We especially focus on the efficient heterologous expression systems that are applicable for the overproduction of wild-type nitrilases and their artificial variants. Biocatalyst forms with industrial potential are also highlighted. The potential industrial applications of nitrilases are classified according to their target products (α-hydroxy acids, α- and β-amino acids, cyano acids, amides). The emerging uses of nitrilases and their subtypes (cyanide hydratases, cyanide dihydratases) in bioremediation is also summarized. The integration of nitrilases with other enzymes into artificial multienzymatic and chemoenzymatic pathways is considered a promising strategy for future applications.
authors.affiliation: Institute of Microbiology of the Czech Academy of Sciences, v.v.i., Vídeňská 1083, 142 20, Prague, Czech Republic. martinko@biomed.cas.cz.
authors.forename: Ludmila
authors.initials: L
authors.lastname: Martínková
authors.affiliation: Institute of Microbiology of the Czech Academy of Sciences, v.v.i., Vídeňská 1083, 142 20, Prague, Czech Republic.
authors.forename: Lenka
authors.initials: L
authors.lastname: Rucká
authors.affiliation: Institute of Microbiology of the Czech Academy of Sciences, v.v.i., Vídeňská 1083, 142 20, Prague, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Nešvera
authors.affiliation: Institute of Microbiology of the Czech Academy of Sciences, v.v.i., Vídeňská 1083, 142 20, Prague, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Pátek
mesh_terms: D000619:Aminohydrolases / Q000235:genetics / Q000378:metabolism*; D001419:Bacteria / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D055162:Biocatalysis; D001673:Biodegradation, Environmental; D030562:Databases, Protein; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005658:Fungi / Q000201:enzymology* / Q000235:genetics; D056186:Metagenomics; D009570:Nitriles / Q000378:metabolism*; D015202:Protein Engineering / Q000379:methods*; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D005656:Fungal Proteins; D009570:Nitriles; D011994:Recombinant Proteins; D000619:Aminohydrolases; C021867:nitrilase
keywords: Aldoxime–nitrile pathway; Biocatalytic applications; Database mining; Heterologous production; Metagenome mining; Nitrilase