中文摘要：

通过选择性培养，从黄河水体中分离纯化出3株能够以苊（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16SrDNA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的初始质量浓度风分别为15．85和12．10μg·L^-1时，培养35d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（ID）变化（最初4d）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．

英文摘要：

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 kineties （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. 10μg. 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.