1株四环素降解菌的分离鉴定及降解特性研究

应用微生物降解四环素具有经济有效和环境友好特点,已成为当前研究的热点。采用选择性培养基,从鸡粪中分离出1株能以四环素作为唯一碳源生长的菌株TC-1,培养7 d降解率为56.2%,初步鉴定为蜡状芽胞杆菌(Bacillus cereus)。从碳氮源组合、培养基初始pH、Na Cl浓度和装液量四方面研究了TC-1降解四环素的特性。结果表明,TC-1在以葡萄糖和酵母粉为碳、氮源生长时效果最优,培养7 d时OD600达2.17;但最优降解率出现在蔗糖和大豆蛋白胨的碳氮源组合中,为46.8%。当培养基初始pH为7时,菌株TC-1生长最好,OD600为0.44,四环素降解率为92.3%。当培养基中Na Cl浓度达15 g/L时,TC-1生长受到抑制,降解率仅为28.6%;培养基装液量为40%时降解率最高,为56.2%。

Isolation, Identification and Characteristics of a Tetracycline-Degradation Bacterium

The application of microorganism for tetracycline degradation possesses the advantages of economic efficiency and environment friendly, and has become a hot topic in current study. A selective media was adopted to isolate and screen the tetracycline-degradation bacteria. A strain TC-1 that could utilize tetracycline as unique carbon resource was isolated from chicken manure, it degradation tetracycline at the rate of 56.2% culturing for 7 d. This strain,named as TC-1,was identified initially as Bacillus cereus according to the morphological features and the sequence analysis of 16S rRNA gene. Carbon and nitrogen sources combination, starting pH of medium, NaCl concentration and liquid filling volume four aspects were analyzed to study the tetracycline degradation performance of strain TC-1. The results showed that strain TC-1 grew the best in the medium with glucose and yeast as carbon and nitrogen sources, OD₆₀₀ was 2.17 after culturing for 7 d. However, the best degradation rate was observed in medium with sucrose and soy peptone as carbon and nitrogen sources combination that having the optimal degradation rate at 46.8%. Strain TC-1 grew the best in medium with pH 7 at the starting culture, the OD₆₀₀ and degrading rate were 0.44 and 92.3%, respectively. However, the growth of TC-1 was inhibited when NaCl concentration in the medium was at 15 g/L and the degradation rate of tetracycline was only 28.6%. When medium liquid filling volume was 40% the degradation rate of tetracycline was 56.2%.