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    杨涛, 孙贤波, 刘勇弟, 蔡正清. 头孢氨苄降解菌的分离鉴定及其降解特性[J]. 华东理工大学学报(自然科学版), 2021, 47(1): 58-66. DOI: 10.14135/j.cnki.1006-3080.20191009009
    引用本文: 杨涛, 孙贤波, 刘勇弟, 蔡正清. 头孢氨苄降解菌的分离鉴定及其降解特性[J]. 华东理工大学学报(自然科学版), 2021, 47(1): 58-66. DOI: 10.14135/j.cnki.1006-3080.20191009009
    YANG Tao, SUN Xianbo, LIU Yongdi, CAI Zhengqing. Isolation, Identification and Degradation Characteristics of Cephalexin Degrading Strain[J]. Journal of East China University of Science and Technology, 2021, 47(1): 58-66. DOI: 10.14135/j.cnki.1006-3080.20191009009
    Citation: YANG Tao, SUN Xianbo, LIU Yongdi, CAI Zhengqing. Isolation, Identification and Degradation Characteristics of Cephalexin Degrading Strain[J]. Journal of East China University of Science and Technology, 2021, 47(1): 58-66. DOI: 10.14135/j.cnki.1006-3080.20191009009

    头孢氨苄降解菌的分离鉴定及其降解特性

    Isolation, Identification and Degradation Characteristics of Cephalexin Degrading Strain

    • 摘要: 从生活污水处理厂污泥中筛选出一株能高效降解头孢氨苄的菌株CQ2,鉴定为苍白杆菌(Ochrobactrum sp.)。考察了温度、pH、混合强度和接种量等对CQ2菌的生长和头孢氨苄降解率的影响,确定最佳培养条件为温度30 ℃、pH 7.0、转速150 r/min、接种量5%(体积分数)。在该条件下培养CQ2菌28 h,对水中初始质量浓度为10 mg/L的头孢氨苄的降解率可达100%;CQ2菌对其他抗生素的降解效果为:培氟沙星<磺胺嘧啶<土霉素<阿莫西林。基于液相色谱-串联质谱仪(LC-MS/MS)测定的降解中间产物,提出了CQ2菌生物降解头孢氨苄的初步路径。

       

      Abstract: A strain CQ2, which can degrade antibiotic cephalexin effectively, was separated from the sludge of domestic sewage treatment plant, and was identified as Ochrobactrum sp. The strain was identified as gram-negative bacteria with a diameter of 4—6 mm. Under 1000 times optical microscope, CQ2 was rod-shaped with a diameter of 0.4—0.6 μm and a length of 1.2—2.5 μm. This strain could not efficiently degrade CX when CX was the only organic carbon source, but could decompose CX rapidly in the presence of glucose, indicating that the strain removed CX through a co-degradation mechanism. The effects of temperature, pH, rotating speed and inoculation percentage on the growth and degradation efficiency of CQ2 were investigated by orthogonal tests. The results showed that CQ2 could effectively degrade cephalexin, and the optimal cultivation conditions are temperature of 30 ℃, pH at 7.0, mixing rate of 150 r/min, and inoculation percentage of 5%. Under the optimal conditions, the cephalexin at initial mass concentration of 10 mg/L could be completely degraded within 28 h. Moreover, under the identical conditions, the tested CQ2 could completely remove amoxicillin at 36 h and significantly degrade terramycin and sulfadiazine, while it played a negligible role on the degradation of pefloxacin due to the inhibition on the CQ2 growth. It is possible that the chromosome of pale bacillus contains specific AmpC gene, which can produce the cephalosporin enzyme ApmC, and therefore has strong resistance to amoxicillin and cefalexin with the structure of β-lactam ring. Based on cephalexin degradation intermediates determined by LC-MS/MS, the biodegradation preliminary pathway of cephalexin by CQ2 was proposed, and 2-hydroxyl-3-phenylpyrazine was the main intermediate of biodegradation after hydrolysis.

       

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