Abstract:

For the biodegradation of p-nitrophenol at low temperature (10℃), p-nitrophenol was used as substrate to investigate the degradation characteristics by a single factor experiment, hydrophobicity, membrane permeability and kinetics experiment. The results showed that Pseudomonas sp. ZL was resistant and degradate p-nitrophenol of 303.71 mg·L^-1, at 10℃. And the optimal degradation pH was 8. At the same time, 0.5% NaCl, and 1.0 g·L^-1 NH₄NO₃ could promote the degradation of p-nitrophenol and significantly reduced lag time for degradation. Under optimal degradation conditions at 10℃, the strain on the nitrophenol inhibit the degradation kinetics fitting with the Aiba model, including the maximum specific growth rate(μ_max) was 0.205 h^-1,the half saturation (K_s) was 3.40 mg·L^-1, the self-inhibition constants (K_i)_{was 166.86 mg·L^-1. Therefore, 166.86 mg·L^-1 was the inhibitory concentration of the bacteria under the condition of low temperature degradation. Compared with other degrading strains, the strain Pseudomonas sp. ZL has larger Ki and μmax/Ks and smaller Ks/Ki value, indicating that the inhibitory effect of p-nitrophenol on the strain is smaller and the effective utilization rate of the strain is higher. That means the inhibition of p-nitrophenol for Pseudomonas sp. ZL was smaller. Utilization rate was higher than other bacteria. It has high application potential in the in-situ repair of low-temperature groundwater and soil pollution.}

Key words: p-nitrophenol, low temperature degrading bacteria, biodegradation, hydrophobicity, membrane permeability, kinetic model

摘要：

以对硝基苯酚在10℃条件下的微生物降解过程为研究对象，融合单因素实验、细胞疏水性实验、细胞膜通透性实验与降解动力学实验探究菌株Pseudomonas sp. ZL对对硝基苯酚的低温降解特性。实验结果表明，在10℃条件下菌株Pseudomonas sp. ZL能够耐受并降解303.71 mg·L^-1的对硝基苯酚，最佳降解条件为pH=8.0，0.5% NaCl，1 g·L^-1 NH₄NO₃，该条件能够显著促进对硝基苯酚的降解速率并大大缩短降解的延迟时间。在10℃、单因素最佳条件下，对硝基苯酚降解菌的抑制降解动力学拟合符合Aiba模型，其中μ_max（最大比生长速率）为0.205 h^-1，K_s（半饱和系数）为3.40 mg·L^-1，K_i（底物抑制系数）为166.86 mg·L^-1，因此166.86 mg·L^-1即为该条件下菌株的低温降解抑制浓度。与其他降解菌株相比，菌株Pseudomonas sp. ZL的K_i和μ_max/K_s较大、K_s/K_i值较小，说明对硝基苯酚对该菌株的抑制作用较小，菌株的有效利用率更高，在原位修复低温地下水及土壤污染方面具有较高的应用潜力。

关键词: 对硝基苯酚, 低温降解菌, 生物降解, 菌株疏水性, 细胞膜通透性, 动力学模型