多溴联苯醚好氧降解菌GH10的筛选及降解特性研究

Isolation of an aerobic bacterial strain GH10 capable of PBDEs-degradation and its biodegradation behaviors

从污水处理厂活性污泥中筛选得到一株多溴联苯醚好氧降解菌,命名为GH10。根据菌株形态特征、生理生化特性、16S r DNA基因序列及系统发育树分析,鉴定为长野雷夫松氏菌（Leifsonia shinshuensis）。该菌能够利用十溴联苯醚作为唯一碳源生长,它对十溴联苯醚的降解率用HPLC法测定。十溴联苯醚质量浓度为10~50 mg/L时,降解效果较好,在十溴联苯醚初始质量浓度为50 mg/L、温度为30℃、摇床转速为150 r/min的条件下避光培养5 d,菌株GH10对十溴联苯醚的降解率可达到59.24%。降解十溴联苯醚的最适条件为温度30℃,p H值7.0,接种量10%,相同条件下添加外加碳源葡萄糖可提高其降解率到90.08%。通过对十溴联苯醚降解动力学的模拟发现,添加外加碳源葡萄糖可以将十溴联苯醚的半衰期从3.91 d缩短至1.45 d。

The paper introduces our research results on the way of isolating, identifying and characterizing the PBDEs-degrading bacterium strain GH10. We have isolated the strain capable of PBDEs-degrading from the activated sludge from a sewage purification plant. The strain we have isolated is known as Leifsonia shinshuensis in hoping to be used for analyzing its morphological features,its physiological and biochemical features,with a 16 S r DNA sequence and the phylogenetic tree. The strain has been found growing well by taking Deca-BDE as the only carbon source,with its degradation efficiency for Deca-BDE being determined by HPLC. It is found that the degradation effect tends to be better with the Deca-BDE initial concentration being from 10-50 mg / L. On the contrary,the degradation rate tends to drop significantly when the initial concentration of Deca-BDE is over 50 mg /L. We have also found that on the condition when the initial concentration of Deca-BDE is 50 mg / L at the temperature of 30 ℃and at the shaking speed of 150 r / min,as the result of dark culture for 5 days,it would be possible to make the degradation rate of Deca-BDE by strain GH10 reach 59. 24%. In the meantime,we have also made an exploration of the effects of strain GH10 on the different temperatures,the p H value and the inoculum rates as well as on the degradation efficiency of Deca-BDE. The optimal condition for degrading Deca-BDE is 30 ℃ of the temperature,the p H value of 7. 0 and the inoculum rate of 10%. However,the degradation rate tends to decrease when the temperature is over or under 30 ℃. Similarly,it tends to increase when the p H value rises from 5. 0 to 7. 0 whereas the degradation rate decreases with the p H value rising further. Thus,it can be found that the degradation efficiency is directly related to the inoculum rate（ 1%-7%）,though the inoculum rate wouldn＇t have any further effect on the degradation efficiency when it rises further. Nevertheless,adding external carbon source glucose can push the degradation rate of Deca-BDE to 90. 08% with the help of strain GH10 under the same condition. To be sure,adding external carbon source glucose can decrease the half life of Deca-BDE from3. 91 days to 1. 45 days by simulating the degradation kinetics of Deca-BDE. Therefore,GH10 has the potential value when used as a bio-remedying agent for removing PBDEs from the contaminated soil and water.