苯系物降解菌PseudomonasputidaSW-3的筛选及其降解苯的研究

Isolation and characterization of benzene degradation strain Pseudomonas putida SW-3

【目的】以苯、甲苯和苯乙烯为唯一碳源,从工业石油废水中筛选苯系物降解菌,分析其降解特性,探讨底物间相互作用对降解情况的影响。【方法】经生理生化和16S r RNA基因分析进行菌种鉴定,采用顶空气相色谱法测定苯系物含量,通过细胞的疏水性、乳化能力、排油圈及透射电镜观察分析菌株降解特性。【结果】经鉴定该菌为Pseudomonas putida,命名为SW-3菌株。最适降解条件下,单位菌体对苯、甲苯和苯乙烯的最大降解速率分别为0.072、0.035和0.019 g/(L·h),苯系混合物的总降解率达79.99%。底物降解实验表明,苯可促进甲苯和苯乙烯的降解,而苯乙烯则能抑制甲苯的降解。菌株的吸附、摄取和降解特性的研究发现,菌株SW-3在自身分泌的表面活性剂的协助下以耗能的方式运输苯。【结论】菌株SW-3具有产生表面活性剂和降解苯系物的能力,且底物间的相互作用能够显著影响菌株对不同底物的降解。

[Objective] The objective of this study is to isolate a bacterium strain from industrial oil wastewater with benzene, toluene and styrene as the sole carbon source, then to analyze the degradation characteristics of the strain and to study the effect of substrate interaction on the degradation. [Methods] The strain was identified with physiological-biochemical and 16S rRNA gene sequence analysis; HS-GC was used to determine benzene series concentration; the degradation characteristics of the strain were analyzed by the hydrophobicity, emulsifying ability, oil displacement and transmission electron microscopy. [Results] The strain was identified as Pseudomonas putida, named SW-3. The maximum degradation rates of benzene, toluene and styrene were 0.072, 0.035 and 0.019 g/（L.h）, and the total degradation rate of benzene mixture was 79.99% under the optimum degradation conditions. The interactions between substrates indicated that the degradation of toluene and styrene was stimulated by benzene, while the degradation of toluene was inhibited in the presence of styrene. The analysis about characteristics of adsorption, uptake and degradation of SW-3 suggested that SW-3 could transport the benzene by the energy-dissipating vesicle transport with the aid of the secreted surfactants. [Conclusion] Strain SW-3 has the ability to produce surfactants and degrade benzene compounds, and the interaction between substrates can significantly affect the degradation of different substrates.