群体感应信号分子对Pseudomonas aeruginosa PAO1生物膜结构及产电性能的影响

Effects of quorum sensing signal molecules on biofilm formation and electricity generation performance of Pseudomonas aeruginosa PAO1

电活性生物膜(EAB)是微生物燃料电池(microbial fuel cell,MFC)的重要组成部分.为揭示群体感应(quorum sensing,QS)信号分子在MFC中对EAB的响应机制,在MFC阳极室接种铜绿假单胞菌,添加两种QS信号分子(N-丁酰基高丝氨酸内酯C4-HSL和喹诺酮PQS),观察其对阳极生物膜形态、结构及MFC产电性能的影响.结果显示:添加终浓度为10μmol/L N-丁酰基高丝氨酸内酯、喹诺酮的MFC的驯化启动期分别比对照组缩短了290.33 h、169.9h,最高输出电压分别提高了18.18%、22.73%,MFC运行后期传质电阻分别减小了9.77Ω、15.15Ω,绿脓素含量分别提高了20.27%、24.32%;扫描电子显微镜(SEM)照片显示添加两种信号分子生物膜的生物量均多于对照组;激光扫描共聚焦显微镜(CLSM)照片显示添加QS信号分子可以明显增大阳极生物膜的厚度并改善活死细胞比例.本研究表明添加QS信号分子显著促进了产电菌Pseudomonas aeruginosa PAO1在MFC阳极表面的成膜速率,强化了其生物活性,提高了EAB与电极间的电子传递效率及MFC的产电性能.

As an important component of microbial fuel cells(MFCs),electroactive biofilm(EAB)is intended to reveal the response mechanism of quorum sensing(QS)signal molecules.Pseudomonas aeruginosa was inoculated in the MFC anode chamber,and two QS signaling molecules(N-butylserine lactone and quinolone)were added to observe their effects on the morphology,structure,and electrical performance of the anode biofilm.Results showed that adding 10μmol/L N-butyl homoserine lactones(C4-HSL)or quinolone(PQS)decreased the start-up stages of the MFC in comparison to the control group by 290.33 h and 169.9 h,respectively;the highest output voltage was increased by 18.18%and 22.73%respectively;the mass transfer resistance was reduced to 9.77Ωand 15.15Ωrespectively,and the pyocyanin content increased by 20.27%and 24.32%respectively.Scanning electron microscopy images showed that the EAB on the anode of the QS signal molecules with added MFCs,which was dominated by bacillus,was richer than that of the control group.Moreover,laser scanning confocal microscopy(CLSM)images showed that the addition of QS signal molecules significantly improved the survivability of cells in the EAB.The results suggest that the addition of QS signal molecules significantly promotes the biofilm-forming rate of electrochemically active bacteria on the anode,which strengthens its bioactivity,improves the electron transfer efficiency between EAB and electrodes,and thus enhances the power generation performance of the MFC system.