1. Dimethylformamide is a novel nitrilase inducer in Rhodococcus rhodochrous.
- Author
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Chhiba-Govindjee VP, Mathiba K, van der Westhuyzen CW, Steenkamp P, Rashamuse JK, Stoychev S, Bode ML, and Brady D
- Subjects
- Biocatalysis, Carboxylic Acids metabolism, Enzyme Induction, Hydrolysis, Industrial Microbiology, Molecular Structure, Niacin metabolism, Nitriles pharmacology, Pyridines metabolism, Rhodococcus drug effects, Tandem Mass Spectrometry, Aminohydrolases biosynthesis, Dimethylformamide pharmacology, Rhodococcus metabolism
- Abstract
Nitrilases are of commercial interest in the selective synthesis of carboxylic acids from nitriles. Nitrilase induction was achieved here in three bacterial strains through the incorporation of a previously unrecognised and inexpensive nitrilase inducer, dimethylformamide (DMF), during cultivation of two Rhodococcus rhodochrous strains (ATCC BAA-870 and PPPPB BD-1780), as well as a closely related organism (Pimelobacter simplex PPPPB BD-1781). Benzonitrile, a known nitrilase inducer, was ineffective in these strains. Biocatalytic product profiling, enzyme inhibition studies and protein sequencing were performed to distinguish the nitrilase activity from that of sequential nitrile hydratase-amidase activity. The expressed enzyme, a 40-kDa protein with high sequence similarity to nitrilase protein Uniprot Q-03217, hydrolyzed 3-cyanopyridine to produce nicotinic acid exclusively in strains BD-1780 and BD-1781. These strains were capable of synthesising both the vitamin nicotinic acid as well as β-amino acids, a compound class of pharmaceutical interest. The induced nitrilase demonstrated high enantioselectivity (> 99%) in the hydrolysis of 3-amino-3-phenylpropanenitrile to the corresponding carboxylic acid.
- Published
- 2018
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