Studies On Biotransformation From 4-hydroxybenzyl Cyanide Into P-hydroxyphenylacetamide

p-Hydroxyphenylacetamide (PHAD) is an important intermediate on synthesize atenolol, a newβ-adrenergic receptor retarder. Atenolol can retard cordisβ- receptors selectively. In clinic, it has long effect which can lower blood pressure and slower heart rate. This paper described the isolation and culture conditions of strains producing nitrile hydratase, which has the ability to hydrolyze 4-hydroxybenzyl cyanide(PHN) to p-hydroxyphenylacetamide, and the conditions of bio-transformation from PHN into PHAD. The results could be useful for bio-transformation preparation of PHAD.7 strains producing PHN nitrile hydratase were isolated. The strain E10a was characterized as Rhodococcus ruber E10a, according to its morphology, physiology and biochemistry combining with 16s rDNA equence. The 16s rDNA equence has been submitted to the genbank database, and Genebank accession number is DQ468352. Culture conditions of the Rhodococcus ruber E10a strain were studied, the results showed that the enzyme activity was not obviously enhanced by adding different inducers. When yeast was tested as nitrogen source and maltose as carbon souce, the Rhodococcus ruber E10a strain grew better and the enzyme activity enhaced. The effects of several metal ions on enzyme were activated by Co²⁺,Zn²⁺, but inhibited by Cu²⁺. It was also testified as Co-NHase.In resting cells research, the optimal pH of the resting cells reaction were ranging from 6.0 to 7.0, and the optimal buffer system is the NaH₂PO₄-Na₂HPO₄ system. When the substrate concentration higher than 1.0(w/v), it will inhibit the enzyme. The enzyme has highest activity on the concentration of 1.0(w/v) of PHN, while it almost lost activity on the concentration of 2.0(w/v). The optimal temperature was 30～45℃. The kinetic constants of were studied, at the optimal conditions, with the PHN as substrate. The results showed that the K_m and v_max were 0.29mol/L and 183.824μmol/min/g for, respectively. E10a resting cells could bio-transform PHN, benzyl cyanide and (2,2)-dimethyl cyclopropanecarbonitrile into amides.