二苯并噻吩脱硫菌Rhodopseudomonas sp. AS-21的脱硫条件优化

以二苯并噻吩(DBT)为模式物筛选得到专一性脱硫菌Rhodopseudomonas sp.AS-21。通过单因素考察实验结果分析温度、pH、碳源、氮源和DBT初始浓度对脱硫率和细胞浓度的影响,得出菌株的最适宜生长和脱硫条件:培养温度为30℃,初始pH为7.5,碳源为10g/L甘油,氮源为2g/L的氯化铵,DBT初始浓度为100mg/L。利用Design-Expert软件进行显著性分析,结果表明温度、pH、DBT浓度影响的显著性较高。采用Box-Behnken Design(BBD)响应曲面法设计三因素三水平共20组实验,得到脱硫率和细胞质量浓度的二次回归模型。在Design-Expert软件模拟的条件下,以响应值最大为目标进行优化求解,结果表明在温度为29.70℃、pH为7.43、DBT初始浓度为105.47mg/L时可得到最大脱硫率(72.32%)及最大菌株生长量(2.311g/L)。经实验验证,所求最优解正确。

OPTIMIZATION OF DIBENZOTHIOPHENE DESULFURIZATION CONDITIONS OF BACTERIUM RHODOPSEUDOMONAS SP. AS-21

The specific DBT desulfurization bacterium Rhodopseudomonas sp. AS-21 was selected. The effects of temperature, pH, carbon source, nitrogen source, and initial concentration of DBT on S removal rate and cell concentration were investigated by single-factor experiments. The best conditions for the growth and desulfurization of AS-21 is 30℃, initial pH 7.5, concentration of glycerin as carbon source 10g/L, concentration of NH4Cl as nitrogen source 2g/L and initial concentration of DBT 100mg/L. The significance analysis results with Design-Expert show that temperature, pH and initial concentration of DBT have higher effects on desulfurization. Box-Behnken Design (BBD) response surface methodology was used to design total 20 experiments with three factors and three levels to obtain quadratic regression model for desulfurization rate and cell mass concentration. The optimization solution of the maximum response values under the simulated conditions by Design-Expert software predicts that the best factors for the highest desulfurization rate and strain growth are 29.70℃，pH 7.43，initial concentration of DBT 105.47mg/L. The highest desulfurization rate and strain growth are 72.32% and 2.311g/L, respectively, which are proven to be right through experiments.