石油烃降解菌对邻苯二酚、苯甲酸钠降解特性的研究

Degradation Characteristics of Catechol and Sodium Benzoate by a Petroleum-degrading Bacterium

邻苯二酚和苯甲酸是苯类化合物代谢过程中两种常见的中间产物,也是工业废水中常见的环境污染物。为了高效去除苯类污染物,考察了高效降解石油中芳香烃组分的菌株 Acinetobacter sp. Tust-DM21 对邻苯二酚和苯甲酸钠的降解,并通过邻苯二酚 1, 2-双加氧酶(C12O)的粗酶特性和苯甲酸 1, 2-双加氧酶的酶活初步研究其代谢过程。在不含碳源无机盐培养基中,菌株 Tust-DM21 能够分别以邻苯二酚和苯甲酸钠为唯一碳源进行生长。通过改变接菌量、底物浓度、pH、温度等方面对该菌降解这两类苯类物质的特性进行研究,对 C12O 的最适 pH、温度和动力学参数以及苯甲酸 1, 2-双加氧酶的酶活进行分析。菌株对邻苯二酚的最大耐受浓度为 700 mg/L,菌株降解 600 mg/L 邻苯二酚的最佳条件为:接菌量 5%、pH6.0、温度 35℃,降解率达 92%以上。菌株可耐受 4 500 mg/L 苯甲酸钠,降解浓度为 1 500 mg/L 苯甲酸钠的最佳条件为:接菌量 3%、pH8.0、温度 35℃,降解率达 95%以上。C12O 的最适 pH 为 8.0,温度 35℃,其动力学参数为 Km=25.68 μmol/L,Vmax=0.131 mol/(mL min);苯甲酸 1, 2-双加氧酶的酶活为 3.53 U。该菌对邻苯二酚、苯甲酸钠有良好的降解效果,具有潜在的应用前景。

Catechol and benzoic acid are two common intermediate products in the metabolism of benzene compounds,and are also common environmental pollutants in industry wastewater. In order to efficiently remove benzene compounds from industry wastewater,the petroleum-degrading strain Acinetobacter sp. Tust-DM21 capable of effectively degrading aromatic compounds were used to investigate the degradation of catechol and sodium benzoate. The metabolic process of sodium benzoate was studied by the crude enzyme characteristics of catechol 1, 2-dioxygenase(C12O)and the enzyme activity of benzoate 1, 2-dioxygenase. In the inorganic salt medium without carbon source, the strain Tust-DM21 was able to grow with catechol and sodium benzoate as the sole carbon source,respectively. The characteristics of the Tust-DM21 degrading these 2 benzene compounds were studied by controlling the dosage of inoculated bacteria,substrate concentration,pH and temperature. Also the optimal pH,temperature and kinetic parameters of C12O and the enzymatic activity of benzoic acid 1,2-dioxygenase were analyzed. As results,the maximum tolerated concentration(MTC)of the strain Tust-DM21 on catechol was 700 mg/L;the optimal conditions for the strain to degrade 600 mg/L of catechol were :5% of inoculum,pH 6.0 and temperature 35℃,respectively;under the optimal condition,the bacteria degraded 92% of catechol. The MTC of the strain on sodium benzoate was 4 500 mg/L. The optimal conditions for the strain to degrade 1 500 mg/L of sodium benzoate were :3% of inoculum,pH 8.0 and temperature 35℃,respectively;under the optimal condition,the bacteria degraded 95% of sodium benzoate. The optimal conditions for the enzymatic reaction of C12O were as follows : pH 8.0 and temperature 35℃;the kinetic parameters of C12O were as follows :Km=25.68 mol/L,Vmax=0.131 mol/(mL min). The enzyme activity of benzoic acid 1,2-dioxygenase was 3.53 U. In conclusion,the strain Tust-DM21 has a strong capability of degrading catechol and sodium benzoate and has a broad prospective application.