一株林可霉素降解菌的筛选鉴定及其降解机制

【背景】抗生素污染越来越引起人们的关注。利用微生物处理抗生素污染被认为是一种环境友好型的方法。【目的】筛选林可霉素高效降解菌并研究其降解机制。【方法】经形态学观察、生理生化鉴定和16S rRNA基因测序分析进行鉴定；通过PCR技术和质谱分析技术对该菌抗性基因和降解产物等进行分析。【结果】从林可霉素菌渣堆肥样本中获得一株高效降解林可霉素的假单胞菌(Pseudomonas RST-1)，该菌在林可霉素浓度为3.0 g/L的牛肉膏蛋白胨培养基上培养40 h后，林可霉素降解率高达57.3%。该菌含有intI1、sul1、sul2等抗性基因，降解产物为去甲基林可霉素和2-丙基-N-甲基脯氨酸。【结论】菌株RST-1具有高效降解林可霉素的能力，推测可能的降解机制为去甲基化和酰胺键水解作用，该菌株降解特性及降解机制研究为林可霉素降解工程菌及其高效降解菌剂的研制奠定了基础。

Isolation and working mechanism characterization of a lincomycin-degrading bacterial strain

Background] Antibiotic pollution has aroused increasing concern. Degradation of environmental antibiotics by biological methods is considered to be an environmentally friendly approach to deal with antibiotic contamination. Objective] To screen out a bacterial strain with efficient lincomycin degradation and study its degradation mechanism. Methods] The strain was identified based on physiological and biochemical characteristics and 16S rDNA sequence. The antibiotic resistance genes were identified by PCR and the degradation products of lincomycin by mass spectrometry. Results] An efficient lincomycin-degrading strain Pseudomonas RST-1 was isolated from a lincomycin mycelia dreg composting sample. After incubation in the beef extract peptone medium with 3.0 g/L lincomycin for 40 h, Pseudomonas RST-1 degraded up to 57.3% of lincomycin. The strain carried antibiotic resistance genes such as intI1, sul1, and sul2. The results of mass spectrometry revealed that lincomycin was degraded into demethyllincomycin and 2-propyl-N-methylproline. Conclusion] The strain RST-1 has the ability to degrade lincomycin efficiently, which may be achieved through demethylation and amide bond hydrolysis. These results laid a foundation for the construction of lincomycin-degrading strains and development of efficient degradation microbial agents.