Enantioselective biocatalytic hydrolysis of β-aminonitriles to β-amino-amides using Rhodococcus rhodochrous ATCC BAA-870

A range of β-aminonitriles (3-amino-3-phenylpropanenitrile and derivatives) were synthesised by reaction of various benzonitriles with acetonitrile and subsequent reduction of the resulting acrylonitrile products. These compounds were hydrolysed to the corresponding amides using the nitrile biocatalytic activity of Rhodococccus rhodochrous ATCC BAA-870. Results showed that the nitrile hydratase enzyme was enantioselective for these compounds, in particular 3-amino-3-p-tolylpropanenitrile and 3-amino-3-(4-methoxyphenyl)propanenitrile and the corresponding amides (up to 85% in one case). The reactions were performed at pH 9.0 after initial attempts at pH 7.0 were unsuccessful, most likely as a result of protonation of the 3-amino group at the lower pH.