一株高效四环素降解菌的分离鉴定及其降解性能研究

Isolation and Identification of A Tetracycline-degrading Bacterium and Optimizing Condition for Tetracycline Degradation

四环素类抗生素在畜牧养殖业中广泛使用,但其结构复杂,难降解,容易在水环境中积蓄,进而对生态环境产生深远影响,许多国家已将抗生素污染列为重要的环境问题展开了相关的基础研究。近年来利用微生物降解环境中的抗生素污染物成为研究热点。采用选择性培养基,从某制药厂排污口的水样中分离筛选到1株具有较高降解四环素能力的菌株4002,经形态观察、生理生化测定和16S r DNA序列分析,将该菌初步鉴定为Advenella sp.。从p H、溶氧量、无机盐等方面对菌株降解四环素的性能进行研究。结果表明,该菌株降解四环素的适宜p H为7.0,在有氧条件下,30℃,150 r/min振荡培养6 d,可使初始浓度为50μg/m L四环素降解率达57.8%。无机盐对降解率有显著影响,添加Fe SO4和Mn SO4对四环素降解有促进作用,Mg SO4影响不大,Ca SO4则有抑制作用。在培养至第8天时,培养液经HPLC检测显示6.022 min处出现新的吸收峰,推测为降解产物。

Tetracycline antibiotics have been widely used in the livestock industry, but its complex structure, difficult to degrade, easy to accumulate in the water environment and produce a far-reaching impact on the ecological environment, antibiotic pollution as an important environmental issues has expanded the related basic research. Microbial degradation of the environment antibiotic pollution in recent years become a hotspot method. The selective media was used to isolate and screen the tetracycline-degrading bacteria. A high efficiency tetracycline-degrading bacterium（4002）was selected from sewage of a pharmaceutical factory. According to the morphological features, physiological and biochemical characteristics and the sequence analysis of 16S rDNA, the strain was identified asAdvenella kashmirensi. Besides, the pH, dissolved oxygen, inorganic salts and other aspects of the strains were analyzied to study the degradation performance of tetracycline. The results showed that, the strain suitable conditions for the degradation of tetracycline are pH7.0, under aerobic condition, 150 r/min and cultured with shaking 6 d, the initial concentration of 50μg/mL tetracycline degradation rate of 57.8%. FeSO4 and MnSO4can promote degradation of tetracycline and little impact on MgSO4, but CaSO4 can inhibit degradation. After cultured for 8 d, the culture solution by HPLC detection showed at 6.022 min emergence of a new absorption peak, which was speculated as the degradation product.