生物法生产丙烯酰胺过程中腈水合酶的抑制和失活

为改进生物法生产丙烯酰胺工艺，研究了腈水合酶催化丙烯腈水合生产丙烯酰胺过程中影响腈水合酶反应速率和酶失活的因素. 实验证明，水合过程中体系pH值的变化基本不影响酶反应速率；底物丙烯腈的浓度低于10 g/L时，酶反应速率与底物浓度成正比，大于75 g/L后，对酶有抑制作用；产物丙烯酰胺显著抑制腈水合酶的活性；菌体细胞内可能存在可以稳定腈水合酶的物质，胞内的腈水合酶在40℃下的半衰期可以达到59.9 h；丙烯酰胺与温度的协同作用是腈水合酶失活的重要原因.

Inhibition and Deactivation of Nitrile Hydratase in the Production of Acrylamide

In order to improve the production of acrylamide (AM), the main effects of pH, temperature, substrate concentration and product concentration on the deactivation of nitrile hydratase (NHase) in the process of biotransformation from acrylonitrile (AN) were investigated. The results indicate that in the process of hydration, system pH value changes from 7 to 8, while NHase reaction velocity remains almost stable in this range. NHase reaction velocity increases with AN concentration when it is below 10 g/L, and NHase is inhibited when the concentration is above 75 g/L. The product acrylamide could inhibit NHase greatly. Cells were observed slowing resistance to thermal deactivation in the process of catalysis, and the half life time of intracellular NHase was as long as 59.9 h. At the same time, the synergistic effect of acrylamide and heat was also an important reason for the deactivation of NHase.