| 摘要: |
| 为发掘四环素高效降解菌株，本研究从以四环素为唯一生长碳源的养鸡场粪便堆肥样品中分离筛选到2株四环素降解菌TC-04和TC-09，并通过形态特征、生理生化特征和16S rRNA基因序列分析，对其进行鉴定。采用单因素试验分别探究不同碳源、氮源、微量元素这3个培养基成分和培养时间、接种量和装液量这3个培养条件对两株菌降解四环素的影响。基于单因素试验结果，通过响应面优化培养基成分，拟合得到二次多项回归模型，确定了降解四环素的最佳培养基成分。经鉴定，菌株TC-04为尼泊尔鞘氨醇盒菌（Sphingopyxis nepalensis），TC-09为京畿大学鞘氨醇杆菌（Sphingobacterium kyonggiense）；TC-04在无机盐培养基（MM）中添加1.5 g/L蔗糖、0.8 g/L蛋白胨和0.3 g/L MnSO4时对四环素的降解率最高，TC-09在MM中添加1.3 g/L葡萄糖、1.2 g/L牛肉膏、0.2 g/L FeSO4时对四环素的降解率最高，预测TC-04和TC-09对四环素的降解率分别为74.29%和86.65%，实际值为74.86%和85.72%；单因素试验结果表明，菌株TC-04和TC-09分别在接种量为2%和1%、装液量为20~60 mL/250 mL、培养6 d时，四环素的降解率最高。本研究获得的2株四环素降解菌，可为环境中残留的四环素降解提供优质微生物种质资源和理论依据。 |
| 关键词: 四环素降解菌 尼泊尔鞘氨醇盒菌TC-04 京畿大学鞘氨醇杆菌TC-09 响应面法 |
| DOI：10.14188/j.ajsh.2022.01.006 |
| 分类号:Q939.96 |
| 基金项目:国家自然科学基金（31700096） |
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| Isolation and identification of two tetracycline degrading bacteria and optimization of degradation conditions |
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YAO Li, KE Maomao, LING Ziwei, DU Shanshan, XUE Fei
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College of Marine and Bio-Engineering， Yancheng Teachers University， Yancheng 224000， Jiangsu， China
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| Abstract: |
| Tetracycline is a broad-spectrum antibiotic produced by actinomycetes. Its chemical structure is relatively stable and easy to accumulate in the environment and affect the ecological environment. In order to explore tetracycline degrading strains， tetracycline was used as the sole carbon source and two strains with the highest tetracycline-degrading ability were identified based on morphological， physiological， biochemical characterization and 16S rRNA gene sequencing. The effects of different carbon sources， nitrogen sources and trace elements on the degradation rate of the strains were tested. Based on the single factor test， the method of response surface analysis was adopted to optimize the medium composition. Furthermore， the culture time， inoculation quantity， and liquid filling quantity of the medium were analyzed to investigate the tetracycline degradation performance of the isolated strains. The isolated strains TC-04 and TC-09 were identified as Sphingopyxis nepalensis and Sphingobacterium kyonggiense， respectively. The highest tetracycline-degrading efficacy of TC-04 was achieved when it was incubated in the minimal medium （MM） added 1.5 g/L sucrose， 0.8 g/L peptone and 0.3 g/L MnSO4， whereas the highest tetracycline-degrading efficacy of TC-09 was obtained in the MM added 1.3 g/L glucose， 1.2 g/L beef extract and 0.2 g/L FeSO4. Under the above optimum conditions， the predicted tetracycline degradation rate of TC-04 and TC-09 was 74.29% and 86.65%， whereas the observed value was 74.86% and 85.72%， respectively. In addition， TC-04 and TC-09 had the best growth and the highest degradation rate when the inoculation ratio was 2% and 1%， respectively， the liquid volume was 20 to 60 mL and cultured for six days. The two tetracycline degradation strains TC-04 and TC-09 obtained in this study provided microbial resources and references for the degradation of tetracycline residues in environment. |
| Key words: tetracycline degrading bacterium Sphingopyxis nepalensis TC-04 Sphingobacterium kyonggiense TC-09 response surface methodology |
