A nitrile hydratase for cyanopyridines... and it's a bit more stable than usual.

There is a paper in Process Biochemistry which describes a new NHase from Aurantimonas manganoxydans which shows improved stability than you can normally expect from a NHase. It is entitled “Efficient cloning and expression of a thermostable nitrile hydratase in Escherichia coli using an auto-induction fed-batch strategy”, and it is by Xiaolin Peia, Hongyu Zhang, Lijun Meng, Gang Xu, Lirong Yang and Jianping Wu. This NHase is four times more rapid at converting 3-cyanopyridine to its corresponding amide as valeronitrile, and the authors emphasize their enzyme's stability though in the world of NHases where nothing is what you might describe as thermophilic, please don't get too expectant! They have a great table of NHase thermostability which I reproduce with their enzyme's data inserted.

 

A nitrile hydratase for cyanopyridines... (but it prefers aliphatic nitriles)

There has been a recent paper in Journal of Molecular Catalysis B on a nitrilase that converted cyanopyridines. This enzyme came from a strain of Pseudomonas putida. There is also a recent paper in the same journal entitled “Discovery of a new Fe-type nitrile hydratase efficiently hydrating aliphatic and aromatic nitriles by genome mining” by Xiaolin Peia, Lirong Yang, Gang Xu, Qiuyan Wang and Jianping Wu.which describes a nitrile hydratase, this time, from a Pseudomonas putida strain (F1) which they have shown to be able to turn over 3-cyanopyridine in a 1L fed batch reactor. Their activity data suggests it actually prefers aliphatic nitriles: acrylonitrile rates as 941 U/mg and valeronitrile as 535 U/mg as compared to 3-cyanopyridine at 26 U/mg. They describe how it was cloned into E. coli, needing the inclusion of an activator protein to get activity. They also include a nice phylogenetic tree showing the spread of known iron type NHases... plenty of examples in the Rhodococcus but spreading outwards into Pseudomonas.

Scaling up a nitrilase based hydrolysis

Efficient Production of (R)-o-Chloromandelic Acid by Recombinant Escherichia coli Cells Harboring Nitrilase from Burkholderia cenocepacia J2315 by Dongzhi Wei and co-workers is published in Organic Process Research and Development at  DOI:10.1021/op400174a.  It being OPRD and from a group working in a Laboratory of Bioreactor Engineering, it’s going to be an interesting read on doing a nitrilase reaction on the larger scale.  We are currently working on scaling up a different nitrilase-based reaction currently from bench scale to the “too heavy to use normal glassware” scale so it’s good to see how others do it.

 

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A nitrilase for cyanopyridines...

Characterization and functional cloning of an aromatic nitrilase from Pseudomonas putida CGMCC3830 with high conversion efficiency toward cyanopyridine by Hong Xu and co-workers in Journal of Molecular Catalysis B: Enzymatic is the first report of cloning of an aromatic nitrilase from Pseudomonas genus. It has a particular penchant for 3-cyanopyridine.