恶臭假单胞菌对沉积物中双酚A的降解及产物分析

Degradation of bisphenol A by Pseudomonas putida in sediments and catabolite analysis

为了深入了解雌激素双酚A在天然水环境介质中的迁移转化行为,采用选择性萃取分离方法对沉积物样品不同组分进行分离,研究了市售恶臭假单胞菌降解沉积物中双酚A的规律。结果表明:恶臭假单胞菌对双酚A的降解过程符合赝一级反应动力学特征,微生物降解双酚A的过程存在一个合适的降解浓度,底物一方面可以诱导降解酶活性的提高,一方面也抑制细菌的生长和生理活动;通过选择性萃取前后沉积物-水体系中双酚A的降解试验,证明沉积物中铁锰氧化物的萃取分离可能增加了有机质的相对含量,使微生物可利用碳源增加,促进了双酚A的降解,而有机质的萃取分离降低了双酚A的降解率。利用GC～MS对降解产物进行分析,发现其主要降解产物之一为十五烷酸甲酯,表明该菌降解双酚A使其苯环断环。

This paper is dedicated to an investigative study of degradation of bisphenol A by pseudomonas putida in sediments and catabolite analysis in hoping to push research in this way further and improve the safety production, transportation and transformation of bisphenol A in the media of natural water body. In this paper, we have adopted the selective extraction techniques along with batch adsorption experiments and statistical analyses to study the adsorption behavior of bisphenol A in different components of sediments, including the best inoculation amount of Pseudomonas sp., the optimum concentration of sediments, even the available degradation ways of bisphenol A via Pseudomonas sp.. The results of our research indicate that in the condition when the initial concentrations of BPA were 10 mg/L, 50 mg/L, and 100 mg/L, it was possible for the growth of the bacteria in the mineral salts cultures to reach the maximum levels at approximately 36 h, 24 h, and 12 h, respectively. Then, the amount of bacteria began to decrease remarkably whereas the degradation reaction of bisphenol A would come to tally with the pseudo first order kinetic characteristics. However, under the condition when the initial concentration was 10 mg/L, it would be easy for the degradation rate to get to its maximum degree （72.86 % ）. Our study also shows that there do exist optimal conditions with the process of Pseudomonas sp. degrading bisphenol A, for, on the one hand, bisphenol A tends to stimulate the activity of degrading enzyme, on the other, it may also inhibit the growth and the physiological activities of the bacteria. In addition, we have also studied the other likely affecting factors of the conditions of BPA-degradation rate, for example, the shaking of flasks. Thus, it can be concluded that .the optimal conditions for BPA degradation should be： the concentration of sediments solution 40 mL/g, and the inoculum amount 8 % . While the selective extraction techniques may influence the bisphenol A degradation in the system of sediments （water）, the removal of Fe/Mn oxides may lead to the increase of the relative contents of organic matters, there- by the available carbon is expected to increase accordingly, which in turn may result in promoting the degradation. However, reagent extraction of the organic matters proves to slow down the degradation rate. The main degrading products are pentadecanoic acid and methyl ester via GC-MS, which indicates the rupture of the phcnyl of bisphenol A as a result of the bacteria degradation.