Isolation,Identification of Nitrile Hydratase-Producing Bacterium and Nitrile Hydratase Characterization

Bacteria strains were isolated from farmland soil,and were initially screened to obtain 11 nitrile hydratase-producing strains by TLC method. Rescreening provided a strain with a high activity of nitrile hydratase,namely Jn-102.The Strain Jn-102 was identified as Bacillus aryabhattai vas combination of morphological,physiological and biochemical characteristics and 16S rDNA sequence analysis. The enzymatic properties showed that the optimum temperature and pH for the nitrile hydratase were 50℃ and 7.0,respectively. The enzyme was stable in the pH range of 6.0~8.0 and below the temperature of 40℃. The enzyme had board substrate specificity for aromatic nitriles and its apparent K_m and V_max were 21.3 mmol/L and 60.2 μmol/(min·mg)for p-hydroxybenzylcyanide,respectively. The nitrile hydratase activity was slightly affected by Co²⁺ and Mg²⁺ and could be inhibited by Zn²⁺. Therefore,strain Jn-102 has potential applications in the industrial production of nitrile hydratase.