高效脱硫菌和甲苯降解菌的筛选、组合及其降解条件的优化

以脱硫菌和甲苯降解菌为研究对象,分别以硫代硫酸钠和甲苯为驯化底物,研究了2类菌种的驯化、筛选、组合及混合菌的降解条件.通过驯化菌源,筛选得到高效脱硫菌4株(Z1、Z2、Z3、B1),甲苯降解菌3株(J1、J2、J3),并优化组合2类菌种得到混合菌的最佳组合方式为(Z1+Z2)-B1-(J1+J3),且其菌体密度组合比例为2∶4∶3.同时以SO2-4的质量浓度和甲苯降解率为控制指标,采用响应面法的中心组合设计(central composite design,CCD)优化混合菌的降解条件,分析得到混合菌的最优降解条件为:pH 6.6,温度30.0℃,接种量3.0%,甲苯添加量3.0μL,硫代硫酸钠加入量4.0 g/L.验证实验表明,在最优条件下混合菌的甲苯降解率为73.9%,培养液中SO2-4的质量浓度为163.9 mg/L,基本与预测结果一致,较优化前有明显提高.

Screening and Combination of Efficient Desulfurizing-bacteria and Toluene Degrading Bacteria and Degradation Condition Optimization of Mixed Bacteria

The paper reports the domestication,screening and combination of the toluene degrading bacteria and desulfurizing-bacteria,investigates the degradation conditions of mixed bacteria,with sodium thiosulfate and toluene as substrate,respectively. Four strains of efficient desulfurizing-bacteria(Z1,Z2, Z3,and B1) and three strains of toluene degradation bacteria(J1,J2,and J3) were obtained by domesticating bacteria sources. Then,the two kinds of strains were combined to obtain the best combination mode for(Z1+ Z2)- B1-(J1+ J3),and the density ratio of thallus 2∶ 4∶ 3. In addition, The central composite design(CCD) of response surface method(RSM) was used for optimizing the degradation condition of the mixed bacteria,SO4 2-concentration and toluene degradation rate as control index. The optimum conditions were as follows: pH 6. 8,temperature 30. 0 ℃,inoculation amount 3. 0%,toluene mass 3. 0 μL/80 mL,and sodium thiosulfate mass 4. 4 g/L. The verified experiment shows that toluene degradation rate can reach 73. 9% and SO2-4concentration of 163. 9 mg/L under the best degradation conditions,which was basically identical to the prediction results,and improved significantly compared with removal performance before optimization.