一株以喹啉为燃料的产电假单胞菌(Pseudomonas sp.)Q1的特性研究

Electricity generation and quinoline degradation by an electrochemically active bacterium,Pseudomonas citronellolis strain Q1

微生物燃料电池(Microbial fuel cell,MFC)阳极微生物的种类和作用机制对MFC的产电性能有着重要影响.从稳定运行了210d,以200mg·mL-1喹啉为燃料的MFC阳极室分离得到一株革兰氏阴性菌,命名为Q1,其16S rRNA基因序列与Pseudomonas citronellolisDSM50332T的同源性为96.9%,属于假单胞菌属(Pseudomonassp.).循环伏安法及构建纯菌MFC方法的测定结果均表明Q1具电化学活性.菌株Q1能利用单一喹啉或喹啉和葡萄糖混合燃料产电.在本试验所用浓度范围内,增加葡萄糖浓度,菌株Q1对应的最高输出电压增加,增加喹啉浓度菌株Q1的产电性能则降低,研究表明,菌株Q1库仑量和库仑效率达到最高时(分别为18.65C和36.56%),存在一个最佳喹啉与葡萄糖浓度比1∶3.在MFC中喹啉的降解效果优于普通厌氧培养,葡萄糖对菌株Q1降解喹啉有促进作用,以喹啉和葡萄糖为混合燃料24h对喹啉的去除率达99.53%,优于以单一喹啉为燃料的情况.循环伏安法和不同更换基质方式试验表明,附着在电极上的菌株Q1对产电起主要作用,Q1的溶解态代谢产物对产电过程起电子介体的作用.

Microbial components of the microbial fuel cells（MFC）,including the constituent species and metabolic mechanism of the anodic microorganisms,are critical to the optimization of electricity generation.An electrogenetic bacterial strain（designated as Q1）was isolated from an MFC,using 200 mg·L^-1 quinoline as the fuel and operating for 210 d.The isolate was identified as a strain of Pseudomonas citronellolis（with a similarity of 96.9%）based on its physiological,morphological characteristics,and 16S rRNA sequence analysis.The electrochemical activity of Q1 was tested with cyclic voltammetry（CV）and by operation of a new MFC inoculated with the strain.Power generation was obtained using the strain and quinoline and/or glucose as the fuel.Increasing the glucose concentration had a positive influence on the maximum voltage while high concentrations of quinoline decreased the voltage output.The optimal ratio of quinoline to glucose was 1∶3,which led to the highest coulomb charges of 18.65 C and columbic efficiency of 36.56%.The quinoline degradation rate with strain Q1 reached 99.53% by 24 h,which were higher than those under the conventional anaerobic conditions.The results showed that Q1 attached to the anode played a major role in power generation and soluble mediators produced by Q1 acted as the electron shuttles.