PT - JOURNAL ARTICLE AU - Lukasz Szydlowski AU - Anatoly Sorokin AU - Olga Vasieva AU - Veyacheslav Fedorovich AU - Igor Goryanin TI - Evolutionary dynamics of microbial communities in bioelectrochemical systems AID - 10.1101/725580 DP - 2019 Jan 01 TA - bioRxiv PG - 725580 4099 - http://biorxiv.org/content/early/2019/08/05/725580.short 4100 - http://biorxiv.org/content/early/2019/08/05/725580.full AB - Bio-electrochemical systems can generate electricity by virtue of mature microbial consortia that gradually and spontaneously optimize performance. To understand selective enrichment of these electrogenic microbial communities, we set up five, 3-electrode reactors using the same inoculum derived from rice wash wastewater and incubated them under a range of applied potentials. We sampled reactors and extracted DNA from anodal, cathodal, and planktonic bacterial communities over 12 weeks. Using a custom-made bioinformatics pipeline, we combined 16S and metagenomic samples to analyze temporal changes in a community composition. We observed some genera that constituted a minor proportion of the initial inoculum, but that within weeks dominated the communities. Our study shows a correlation between community structure and applied potential. For instance, the abundance of Geobacter increased from 423-fold to 766-fold between −153 mV and 147 mV, respectively. Full metagenomic profiles of bacterial communities were obtained from reactors operating for 12 weeks. Functional analyses of metagenomes revealed metabolic changes between different species of the dominant genus, Geobacter, suggesting that optimal nutrient utilization at the lowest electrode potential is achieved via genome rearrangements and a strong inter-strain selection, as well as adjustment of the characteristic syntrophic relationships. Our observations reveal a certain degree of metabolic plasticity of electrochemically active bacteria and their communities in adaptation to adverse anodic and cathodic environments.