【摘要】 通过选择性培养,从黄河水体中分离纯化出3株能够以(Chr)和苯并[a]芘(B[a]P)为唯一碳源和能源进行生长的细菌HKS-1,HKS-2和HKS-3,采用16S rDNA序列分析,初步断定HKS-1为杆菌属或无芽孢杆菌属的一个种,HKS-2和HKS-3为芽孢杆菌菌株.微生物降解实验表明,Chr和B[a]P在前25d的降解符合零级动力学规律,3株细菌的混合菌群对Chr和B[a]P有良好的降解效果,泥沙的加入能够促进微生物数量的增长,从而促进Chr和B[a]P的降解.当Chr和B[a]P的初始质量浓度0ρ分别为15.85和12.10μg.L-1时,培养35 d后不含泥沙体系中Chr和B[a]P的降解率分别为45.79%和37.36%;含泥沙体系中Chr和B[a]P的降解率分别为58.76%和51.69%.进一步采用膜实验对比研究了多环芳烃在水相和颗粒相的降解速率.结果表明,当用零级动力学对Chr和B[a]P的质量浓度(ρ)变化(最初4 d)进行拟合时,Chr和B[a]P在颗粒相的降解速率分别约为其在水相降解速率的3和4倍.更多还原

【Abstract】 Three indigenous PAHs-degrading bacterial strains HKS-1,HKS-2 and HKS-3 were obtained by selective culture from The Yellow River.Sequence analysis of 16 s rDNA showed that HSK-1 belongs to Bacterium sp.,HSK-2 and HSK-3 belongs to Bacillus sp.Biodegradation experiments showed that PAHs degradation in water-sediment systems could be fitted with zero-order kinetics(the first 25 days were fitted).These microbial strains degraded chrysene and benzo[a]pyrene well,the presence of particulates promoted degradation.With the initial concentrations of chrysene and benzo[a]pyrene in water/sediment systems at 15.85 and 12.10 μg·L-1,45.79% and 37.36% of chrysene and benzo[a]pyrene respectively were degraded after 35 d incubation without sediment;at the same time,58.76% and 51.69% of chrysene and benzo[a]pyrene respectively in the system were degraded with sediment.Water and PAHs can cross PTFE membrane but bacteria and sediment cannot,a membrane experiment was carried out to compare the biodegradation rates of PAHs in water phase and in particulate phase.It was found that when zero-order biodegradation kinetics was fitted(the first 4 days),degradation rate for chrysene and benzo[a]pyrene at the particulate phase were three and four times of that in water phase,respectively.更多还原