Microorganisms with high tetracycline (TC) degradation efficiencies are required for biological processes for TC-containing wastewater treatment. With multiple enrichment cultures, a TC-degrading strain TR5 was isolated from chicken manure mixture in a large broiler farm, which was identified as Klebsiella pneumoniae by 16S rRNA gene sequencing and biochemical properties. Strain TR5 could degrade TC quickly (∼90% within 36 h) with the initial TC concentration of 200 mg/L under optimized conditions via single-factor experiment coupled with RSM. Strain TR5 could detoxify TC and generate much less toxic products as long as cultured more than one day. Three TC-degrading pathways were proposed based on 8 possible products. A transformant containing a plasmid from TR5 acquired TC-degrading ability, indicating that TC-degrading genes were located on this plasmid. Complete sequencing of pYK5 showed that isomerase-, oxidoreductase-, and transferases-encoding genes were found and were inferred to be involved in TC degradation. TR5 may not degrade TC completely and it can utilize some carbon-containing compounds derived from TC via the effect of formylglutathione hydrolase-encoding gene. Our findings showed that strain TR5 could be a promising agent for wastewater treatment, and genes involved in TC degradation are worthy of further investigations for enzyme preparations development.

中文翻译：

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四环素降解的克雷伯菌。TR5株：拟议的降解途径和可能涉及的基因。

具有高四环素（TC）降解效率的微生物是含TC废水处理的生物过程所必需的。通过多种富集培养，在一个大型肉鸡场中从鸡粪混合物中分离出了TC降解菌株TR5，通过16S rRNA基因测序和生化特性将其鉴定为肺炎克雷伯菌。在优化条件下，通过单因素实验和RSM结合，初始TC浓度为200 mg / L时，菌株TR5可以快速降解TC（36 h内约90％）。只要培养超过一天，菌株TR5即可解毒TC，并产生毒性更小的产品。根据8种可能的产品，提出了3种TC降解途径。含有来自TR5的质粒的转化子具有TC降解能力，表明TC降解基因位于该质粒上。对pYK5的完整测序表明，发现了异构酶，氧化还原酶和转移酶编码基因，并推断它们与TC降解有关。TR5可能无法完全降解TC，它可以通过甲酰谷胱甘肽水解酶编码基因的作用，利用某些源自TC的含碳化合物。我们的研究结果表明，TR5菌株可能是有希望的废水处理剂，涉及TC降解的基因值得进一步研究以开发酶制剂。TR5可能无法完全降解TC，它可以通过甲酰谷胱甘肽水解酶编码基因的作用，利用某些源自TC的含碳化合物。我们的研究结果表明，TR5菌株可能是有希望的废水处理剂，涉及TC降解的基因值得进一步研究以开发酶制剂。TR5可能无法完全降解TC，它可以通过甲酰谷胱甘肽水解酶编码基因的作用，利用某些源自TC的含碳化合物。我们的研究结果表明，TR5菌株可能是有希望的废水处理剂，涉及TC降解的基因值得进一步研究以开发酶制剂。