纯菌株与混合菌株在MFC中降解喹啉及产电性能的研究

Electricity Generation and Quinoline Degradation of Pure Strains and Mixed Strains in the Microbial Fuel Cell

微生物燃料电池(microbial fuel cell,MFC)阳极微生物菌群组成与MFC产电性能有重要关系.从稳定运行了210 d以上,以200 mg.L-1喹啉为燃料的MFC阳极室分离提纯出4株兼性厌氧菌Q1、b、c和d,分别代表原MFC中所有4类不同菌落形态的可培养菌.16S rDNA序列分析结果表明,菌株Q1、c和d属于假单胞菌属(Pseudomonas sp.),菌株b属于伯克霍尔德菌属(Burkholderia sp.).通过构建双室MFC,以200 mg.L-1喹啉和300 mg.L-1葡萄糖为混合燃料,以铁氰化钾为电子受体测定各菌株产电能力,结果表明菌株b、c和d均为非产电菌.产电菌Q1与非产电菌b、c、d复合产电电荷量依次为3.00、3.57和5.13C,库仑效率依次为3.85%、4.59%和6.58%,产电菌与非产电菌对燃料的降解利用存在竞争关系,使得复合菌产电能力比产电菌Q1单独时的产电能力差.在MFC中,非产电菌与产电菌复合产电时24h内对喹啉的去除率均可以达到100%,降解喹啉效果优于4株菌单独构建的MFC,即混合菌更有利于利用复杂碳源.GC/MS的测定结果表明,产电菌株Q1构建的纯菌MFC和原混合菌MFC周期结束时出水中存在的喹啉代谢产物均为2-羟基喹啉和苯酚.

Microbial flora composition of microbial fuel cells（MFC） is important to the electricity generation.Four bacterium strains Q1,b,c and d which represent all different morphology of culturable bacterium were isolated from a MFC using 200 mg.L-1 quinoline as the fuel and operating for at least 210 days.Strains Q1,c and d were Pseudomonas sp.based on 16S rDNA sequence analysis,while strain b was Burkholderia sp.Double-chamber MFCs using 200 mg.L-1 quinoline and 300 mg.L-1 glucose as the fuel and potassium ferricyanide as the electron acceptor were constructed.Results showed that strain b,c and d were non-electrogenesis.The electrical charges of MFC inoculated electrogenesis strain Q1 with non-electrogenesis strain b,c and d respectively were 3.00,3.57 and 5.13C,and the columbic efficiency were 3.85%,4.59% and 6.58%,which were all lower than that inoculated with pure Q1,because of the interspecific competition of electrogenesis and non-electrogenesis bacteria.Combinations of Q1 with the other three strains respectively resulted in 100% of quinoline degradation rates within 24h,which is better than pure cultures,that is,mixed microbial populations perform better in MFC when complex organics are used as the fuel.GC /MS analyses showed that only 2（1H）-quinolinone and phenol existed in the effluent of the MFC,which was inoculated with only Q1 or mixed bacteria.