MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China.
School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin 300072, China.
Biosens Bioelectron. 2018 Dec 15;121:118-124. doi: 10.1016/j.bios.2018.08.066. Epub 2018 Aug 31.
Cathodic oxygen reduction catalyzed by autotrophic bacteria instead of a precious metal is a promising method to make use of microbial fuel cells (MFCs) in wastewater treatment with electricity production. However, the ecology of electrotrophic microbial consortia in wastewater systems that function as the catalyst for cathodic oxygen reduction is complicated and the electron transfer mechanisms are still unknown, which prevents further improvements of the biocathode performance. Enriched by the repeated transfer of a mature electrotrophic microbial consortia to new cathodes over 10 generations in 230 days, the start-up time was shortened from 21.4 to 7.6 days and the maximum current densities over the potential range of 0.5 to - 0.3 V increased by up to 112%, from 75 ± 5 A m to 159 ± 3 A m, which was further confirmed in half-cell biocathode systems. The electrotrophic microbial consortia approached a relatively stable state after 8 generations. Acinetobacter, which is a member of Proteobacteria, was selectively enriched after 10 generations, which was closely related to the current production. Nitrospiraceae and Nitrosomonas may jointly perform a nitrogen cycling metabolic process and promote cathodic bioelectron transfer. Our findings confirmed that the electrotrophic microbial consortia on the cathode was able to be specifically evolved, leading to higher electroactivity, and also revealed which bacteria in fresh water are closely related to cathodic electron transfer.
自养细菌催化阴极氧还原代替贵金属是利用微生物燃料电池（MFC）在废水处理中同时产电的一种很有前途的方法。然而，在废水系统中作为阴极氧还原催化剂的电营养微生物群落的生态学是复杂的，电子传递机制仍不清楚，这阻碍了生物阴极性能的进一步提高。通过在 230 天内将成熟的电营养微生物群落反复转移到新的阴极 10 代，启动时间从 21.4 天缩短到 7.6 天，在 0.5 到-0.3 V 的电位范围内的最大电流密度增加了 112%，从 75±5 A m增加到 159±3 A m，在半电池生物阴极系统中得到了进一步证实。电营养微生物群落经过 8 代后接近相对稳定的状态。经过 10 代后，变形菌门的不动杆菌被选择性富集，这与电流产生密切相关。硝化螺旋菌科和亚硝化单胞菌可能共同执行氮循环代谢过程并促进阴极生物电子转移。我们的研究结果证实，阴极上的电营养微生物群落能够被特异性进化，从而提高电活性，同时也揭示了淡水环境中哪些细菌与阴极电子转移密切相关。
