Catalase catalyzes the decomposition of H₂O₂ to H₂O and O₂, and has a wide range of industrial applications. However, most catalases used in the textile and paper industries are often subjected to high-alkaline challenges which makes it necessary to develop alkaline catalase. In this study, a catalase from Corynebacterium glutamicum was expressed in Escherichia coli, and the expression conditions were optimized. The recombinant catalase was purified by Ni-chelating affinity chromatography, and the recombinant enzyme was characterized. The optimal conditions of producing the recombinant catalase were: an IPTG concentration of 0.2 mmol/L, a culturing temperature of 25 °C and a culturing time of 11 h. The purified catalase had a specific activity of 55 266 U/mg, and it had a high activity in the pH range of 4.0 to11.5, with the highest activity at pH 11.0. When treated in pH 11.0 for 3 h, the enzyme retained 93% of its activity, indicating that the enzyme was qualified with a favorable stability under high-alkaline condition. The recombinant catalase had maximal activity at 30 °C, and showed a satisfactory thermal stability at a range of 25 °C to 50 °C. The apparent Km and Vmax values of purified catalase were 25.89 mmol/L and 185.18 mmol/(minmg), respectively. Besides, different inhibitors, such as sodium dodecyl sulfate (SDS), urea, NaN₂, β-mercaptoethanol, and EDTA had different degrees of inhibition on enzyme activity. The catalase from C. glutamicum shows high catalytic efficiency and high alkaline stability, suggesting its potential utilization in industrial production.
过氧化氢酶能催化过氧化氢分解为水和氧气，在工业上有着较为广泛的应用。然而，纺织和造纸工业的特殊的高碱性环境，使得开发碱性过氧化氢酶有着重要的应用价值。利用大肠杆菌表达来自于谷氨酸棒杆菌的过氧化氢酶，对其表达条件进行了优化，并通过镍柱亲和层析的方法分离纯化重组蛋白，然后表征纯酶的酶学性质。最适表达条件为：诱导剂IPTG 浓度0.2 mmol/L，诱导温度25 ℃，诱导时间11 h。过氧化氢酶比酶活达到55 266 U/mg，具有较高的催化活性。该酶具有相当宽泛的pH 值适应范围，在pH 4.0–11.5 范围内均具有较高的酶活性，并在pH 11.0条件下表现出最高的酶活性。将纯酶在pH 11.0 的溶液中处理3 h 时剩余酶活为93%，说明该酶在高碱条件下有良好的稳定性。该酶最适温度为30 ℃，在25–50 ℃热稳定性较好。其动力学参数Km 为25.89 mmol/L，Vmax 为185.18 mmol/(minmg)。抑制剂十二烷基硫酸钠 (SDS)、尿素、NaN₂、β-巯基乙醇、EDTA 对酶活有不同程度的抑制作用。来源于谷氨酸棒杆菌的过氧化氢酶具有较高的催化效率、良好的碱耐受性，在工业生产中有较好的应用前景。.
Keywords: Corynebacterium glutamicum; alkali resistance; catalase; enzymatic properties; heterologous expression.