中文摘要：

本文在对普通培养条件下异养微生物粪产碱杆菌（Alcaligenes faecalis,A.faecalis）反硝化特征研究的基础上,运用电化学方法于一定电势下（-0.15 V、-0.06 V、＋0.06 V vs.NHE）模拟半导体矿物导带光电子能量,探讨不同能量的光电子对A.faecalis反硝化特性及细胞生长代谢的影响.实验显示,在普通培养条件下,A.faecalis在有氧和无氧环境中均不能还原NO3-,但还原NO2-效果明显.在模拟光电子实验体系中,A.faecalis可在不同电势（-0.15 V、-0.06 V、＋0.06 V）的阴极石墨电极表面附着并形成具有反硝化活性的菌膜;其中,外加电势为-0.15V的实验组菌膜量最多,其NO3-去除率也最高,10天达到52％;-0.06 V体系略低,NO3-去除率为30.5％,＋0.06 V体系菌膜量最少,其NO3-去除效果也最差,仅为10.6％.而在不添加微生物的电化学体系中,3个外加电势下的NO3-浓度均未发生明显变化.本实验研究结果证明了一定能量的半导体矿物光电子可影响土壤异养微生物A.faecalis的生长代谢及反硝化行为.

英文摘要：

On the basis of studying the denitrifying capability of batch cultured Alcaligenes faecalis （A.faecalis）,the electrochemical method was applied by poising different cathode potentials （-0.15 V,-0.06 V,＋ 0.06 V vs.NHE） to simulate the energy of photoelectrons from conduction bands of semiconducting minerals.Based on the results obtained,the authors studied the influence of exogenous electrons with different energy levels on the growth and denitrification capability of A.faecalis in the electrochemical system.The result showed that in the case of batch culture,A.faecalis could reduce nitrite significantly under aerobic or anaerobic conditions,rather than reducing nitrate.In simulated photoelectron systems,the formation of cathodic biofilms with denitrification activity on the graphite electrode was observed at all three cathode potentials （-0.15 V,-0.06 V,＋ 0.06 V vs.NHE）.Quantitatively,the bacteria was obviously colonized on the cathode poised at -0.15 V,the removal rate of nitrate by A.faecalis was simultaneously the highest （52％ after 10 d）,compared with 30.5 ％ reduction rate of NO3-in the-0.06 V system.Much fewer bacteria were attached sparsely to the electrode surface when the poised potential was at ＋ O.06 V,resulting in the lowest removal rate of 10.6 ％.In the sterile systems （three cathode potentials without bacteria）,the concentration of NO3-only decreased a little.The results of this study indicate that photoelectrons with different energies from semiconducting minerals influence the metabolism and denitrification capability of heterotrophic microbe-A.faecalis.