Enantioselective biotransformations using rhodococci

The use of enzymes and whole cells in enantioselective biotransformation reactions is briefly reviewed. A Rhodococcus strain is shown to possess nitrile hydratase and amidase activity. The organism can be used for the enantioselective biotransformation of racemic -amino amides to (S) -amino acids with an enantiomeric excess (ee) of > 98%. Enantioselectivity is effectively time independent allowing easy quantitative conversion of racemic mixtures into enantiomerically pure -amino amides and -amino acids. The reaction is effective for a wide range of - substituents. The pH-dependence of the reaction indicates that the -amino amide is bound to the amidase enzyme in its neutral unprotonated form.