为了研究菌株Diaphorobacter sp.PD-7在有氧条件下降解低浓度苯酚同时反硝化的特性,采用单因素试验,摇床转速180 r/min时,最佳降酚条件为200 mg/L乙酸钠和300 mg/L苯酚同时作为碳源,培养液初始pH为7.0,温度30 ℃,20 h内对初始浓度300 mg/L苯酚去除率达97.3%.培养液pH为中性时,硝酸盐还原酶(NAR)与亚硝酸盐还原酶(NIR)的最适反应温度分别为35 ℃、40 ℃.用米门方程对酶促反应动力学模拟,拟合曲线与实验测定值相关性良好,参数分别为Km=0.76 μmol/L、vmax=42.02×10-3 U/min和Km=1.49 μmol/L、vmax=32.79×10-3 U/min.推测NIR可能是该菌株反硝化过程中的限速酶,菌株PD-7主要通过细胞同化作用与反硝化作用脱氮,且该菌株有着完整的反硝化途径.%Single factor experiments was used to study the characteristic of simultaneous low concentration of phenol degradation of the strain Diaphorobacter sp.PD-7 and its denitrification.At the shaking speed of 180 r/min, the optimum degradation condition were as follow: 200 mg/L soudium acetate and 300 mg/L phenol as carbon source at the same time, initial pH 7.0, temperature 30 ℃.The strain degraded 97.3% of 300 mg/L phenol in 20 h.The optimal reaction temperature of nitrate reductase (NAR) and nitrite reductase (NIR) were 35 ℃ and 40 ℃, respectively, when the nutrient solution pH value is neutral.The process of enzymatic reaction was simulated using Michaelis-Menten equation.The fitted curve had a good correlation with test measured.The parameters were Km=0.76 μmol/L,vmax=42.02×10-3 U/min, and Km=1.49 μmol/L,vmax=32.79×10-3 U/min.Speculated that NIR may be the rate-limiting enzyme in the denitrification process, Strains PD-7 denitrified mainly through assimilation and denitrification denitrification, and the strain has a complete denitrification pathways.
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