Investigation On The Microbial Community Of Functional Bioelectrochemistry Systems

With the development of bioelectrochemistry technology, much more corresponding environmental applications have been extended. Microbes play an important role in bioelectrochemistry systems, which relate to the environmental function of bioelectrochemistry systems. Based on the next-generation sequencing, this work focus on the microbial community of functional bioelectrochemistry systems by diging out the big sequncing data. The microbial communities of s ulfate, nitrate and ammonia removal in bioelectrochemistry systems were disscused, respectively. The microbial community analysis is helpful for explaining the biological process, which provides a theoretical support for the environmental applications of bioelectrochemistry systems. The main results are following:1. This study comprehensively explored the bacterial communities of bioelectrochemical systems under three p Hs using 454 pyrosequencing. This study demonstrated that the indexes of phylotype richness and phylogenetic diversity were positively correlated across the p H gradient in the BESs. Among dominant OTUs, the OTUs which were highly similar to D. butyrativorans, Desulfovibrio marrakechensis and Desulfomicrobium sp. might participate in removing sulfate. Based on genus level, Desulfomicrobium and Sulfuricurvum play conducing and adverse roles for sulfate removal in alkaline condition, respectively. Desulfovibrio contributed to removing sulfate in the neutral and acidic condition, while Thiomonas mainly weakened the performance of sulfate removal in neutral p H condition. These results further clarified how p H condition directly affected the bacterial communities, which consequently affected the performance of sulfate pollutant treatment.2. The study shows that MFC with smaller external resistor has increased performance of current production and rates of nitrate removal. Pyrosequencing analysis using 16 S r RNA genes indicated that autotrophic denitrifying biocathode in MFCs can sustain a great number of active bacterial OTUs and bacteria from Proteobacteria, Bacteroidetes, Chloroflexi, and Planctomycetes were dominant members in the autotrophic denitrifying biofilms. Classes of Alphaproteobacteria, Anaerolineae, and Phycisphaerae seemed to benefit the performance of current production and nitrate removal. Twentynine OTUs dominated the cathodic biofilms, and both autotrophic and heterotrophic denitrification seemed to be very important processes for nitrate removal after constructing a relationship between some dominant OTUs and their functions based on existent literature.3. Through explore the abiotic and biotic ammonia removal in bioelectrochemistry systems with different resistances, the results showed that abiotic electromigration was positive related to current response. The less resistances meant to the more current, which result in the more electromigration. The biotic ammonia removal of anodic microorganism was negative related to loading resistances. For understanding the biological process, the high-throughput sequencing was applied to identify the 16 S r RNA gene of bacteria. The ammonia of wastewater was transformed to nitrate by nitrifying bacteria, and then the nitrate, as electron acceptor, was further transformed to free nitrogen by denitri fying bacteria, who can use substances or electrode as the eletron donor. While, Azotobacteria transformed the nitrogen to nitrogen-containing compound, which weakened the biotic ammonia removal. The electrochemical activity bacteria promote the eletron tr ansfer among biofilm, and enhance the cooporation of redox metabolism.