一株金霉素降解新菌株的分离鉴定及降解条件优化

四环素类抗生素在畜牧业中的广泛应用对人类和动物具有潜在的危害。以金霉素制药厂污泥为原料，从中分离出一株能够高效降解金霉素的纯菌株，命名为ZL-1。经形态学观察、革兰氏染色和16S rDNA鉴定，表明该菌株属于革兰氏阴性菌、不动杆菌属（Acinetobacter sp.）。通过正交试验研究了碳源、温度、pH、初始金霉素浓度、接种量对菌株ZL-1降解金霉素效果的影响。结果表明，温度、接种量和初始金霉素浓度对该菌株降解金霉素的影响较大。以正交试验的结果为依据，采用响应面法优化该菌株对金霉素的降解条件，确定了最优条件为金霉素初始浓度134.864 mg/L，温度34.409 ℃，接种量5.223%（体积比）。在最佳降解条件下，金霉素的实际降解率为93.70%，预测降解率为93.723%，表明预测模型的预测值与实际的降解效果较贴合。

Isolation,identification and degradation conditions optimization of a new bacterial strain degrading chlortetracycline

The extensive application of tetracycline antibiotics in stock farming has brought potential hazards to people and animals. A well-functioning chlortetracycline-degrading pure bacteria strain was isolated from the sludge of the chlortetracycline pharmaceutical factory. The strain was named ZL-1 and identified to belong to gram-negative bacteria and Acinetobacter sp. based on the morphological observation, gram staining and 16S rDNA sequencing identification. Furthermore, the effects of carbon source, temperature, pH, initial chlortetracycline concentration and inoculation amount on the chlortetracycline degradation performance of ZL-1 were analyzed by the orthogonal test. The results showed that the temperature, inoculation amount, and initial chlortetracycline concentration had a greater impact on the chlortetracycline degradation efficiency. Based on the results of the orthogonal test, the chlortetracycline degradation conditions of the bacteria were optimized by the response surface method, and the optimal conditions for degrading chlortetracycline were determined. The optimal conditions were the initial chlortetracycline concentration 134.864 mg/L, the temperature 34.409 ℃, and the inoculation concentration 5.223%. Under the optimal conditions, the actual degradation efficiency of chlortetracycline was 93.70%, whereas the predictive value was 93.723%, indicating that the proposed model had high accuracy.