Abadikhah Marie, Liu Ming, Persson Frank, Wilén Britt-Marie, Farewell Anne, Sun Jie, Modin Oskar
Water Environment Technology, Architecture and Civil Engineering, Chalmers University of Technology, Gothenburg, Sweden.
Key Laboratory of Optoelectronics Technology, Beijing University of Technology, Beijing, 100124, China.
Biofilm. 2023 Oct 10;6:100161. doi: 10.1016/j.bioflm.2023.100161. eCollection 2023 Dec 15.
In a microbial electrolysis cell (MEC), the oxidization of organic compounds is facilitated by an electrogenic biofilm on the anode surface. The biofilm community composition determines the function of the system. Both deterministic and stochastic factors affect the community, but the relative importance of different factors is poorly understood. Anode material is a deterministic factor as materials with different properties may select for different microorganisms. Ecological drift is a stochastic factor, which is amplified by dispersal limitation between communities. Here, we compared the effects of three anode materials (graphene, carbon cloth, and nickel) with the effect of dispersal limitation on the function and biofilm community assembly. Twelve MECs were operated for 56 days in four hydraulically connected loops and shotgun metagenomic sequencing was used to analyse the microbial community composition on the anode surfaces at the end of the experiment. The anode material was the most important factor affecting the performance of the MECs, explaining 54-80 % of the variance observed in peak current density, total electric charge generation, and start-up lag time, while dispersal limitation explained 10-16 % of the variance. Carbon cloth anodes had the highest current generation and shortest lag time. However, dispersal limitation was the most important factor affecting microbial community structure, explaining 61-98 % of the variance in community diversity, evenness, and the relative abundance of the most abundant taxa, while anode material explained 0-20 % of the variance. The biofilms contained nine metagenome-assembled genomes (MAGs), which made up 64-89 % of the communities and were likely responsible for electricity generation in the MECs. Different MAGs dominated in different MECs. Particularly two different genotypes related to competed for dominance on the anodes and reached relative abundances up to 83 %. The winning genotype was the same in all MECs that were hydraulically connected irrespective of anode material used.
在微生物电解池（MEC）中，阳极表面的产电生物膜促进有机化合物的氧化。生物膜群落组成决定了系统的功能。确定性因素和随机因素都会影响群落，但不同因素的相对重要性却知之甚少。阳极材料是一个确定性因素，因为具有不同特性的材料可能会选择不同的微生物。生态漂变是一个随机因素，它会因群落间的扩散限制而放大。在此，我们比较了三种阳极材料（石墨烯、碳布和镍）的影响以及扩散限制对功能和生物膜群落组装的影响。十二个MEC在四个水力连接的回路中运行56天，并在实验结束时使用鸟枪法宏基因组测序分析阳极表面的微生物群落组成。阳极材料是影响MEC性能的最重要因素，解释了在峰值电流密度、总电荷产生和启动滞后时间中观察到的54 - 80%的方差，而扩散限制解释了10 - 16%的方差。碳布阳极产生的电流最高且滞后时间最短。然而，扩散限制是影响微生物群落结构的最重要因素，解释了群落多样性、均匀度以及最丰富分类群相对丰度中61 - 98%的方差，而阳极材料解释了0 - 20%的方差。生物膜包含九个宏基因组组装基因组（MAG），它们占群落的64 - 89%，可能是MEC中发电的原因。不同的MAG在不同的MEC中占主导地位。特别是两种与 相关的不同基因型在阳极上争夺优势，相对丰度高达83%。在所有水力连接的MEC中，无论使用何种阳极材料，获胜的基因型都是相同的。
