【摘要】 通过在液体培养基中添加苯并[a]芘(B[a]P)作为唯一碳源反复驯化培养,从长期受石油烃和多环芳烃(PAHs)污染的土壤中分离出8株能够降解B[a]P的细菌,其中一株细菌(命名为BB-1)具有最大降解效果。采用16s RNA基因测序结果表明,BB-1与巨大芽孢杆菌(Bacillus megaterium)同源性为100%。为了研究BB-1的降解特性,在pH7.0、30℃条件下培养8 d,菌株B[a]P的降解率高达66.36%。为了考察培养基初始pH和外加蔗糖浓度对BB-1降解B[a]P的影响,30℃下振荡培养8 d,当设置培养基初始pH为4.0、6.0、8.0和10.0时,BB-1对B[a]P的降解率分别为12.14%、39.61%、55.21%和30.03%,可见pH为8.0时其降解效果最优;当添加0.1%蔗糖和0.5%蔗糖为外加碳源时,菌株BB-1对B[a]P的降解率分别为70.56%和74.89%,表明0.5%蔗糖的降解效果最优。更多还原

【Abstract】 Eight bacteria strains were isolated from the soil contaminated with petroleum hydrocarbons and polycyclic aromatic hydrocarbons(PAHs)using repeated subcultures in liquid medium with added benzo[a]pyrene(B[a]P)as the sole carbon source. One of the bacterial strains named BB-1 had an optimal degradation effect(100% homologous to Bacillus megaterium)through the 16 s RNA gene sequencing method. In order to explore the degradation character of BB-1,the strain was cultured under pH =7.0,30 ° C for 8 days, after which the B[a]P degradation rate reached a maximum of 66.36%. In order to investigate the degradation rate of BB-1 under varying conditions of initial pH and additional sucrose concentration in the culture medium, the incubation was carried out at 30 °C for 8 days, with various values of initial pH including 4.0, 6.0, 8.0, and 10.0. The results showed that the degradation rates of B [a]P were 12.14%, 39.61%, 55.21%,and 30.03%, respectively. In other words, the highest degradation efficiency was achieved for pH 8.0. With the addition of 0.1% and 0.5%sucrose as an additional carbon source, the degradation rate of B [a]P reached 70.56% and 74.89%, respectively. It was thus clear that the highest degradation efficiency occurred in the media with the addition of 0.5% sucrose.更多还原