School of Environment, Henan Normal University, Xinxiang, Henan, P. R. China.
School of Resource and Environmental Sciences, Henan Institute of Science and Technology, Xinxiang, Henan, P.R. China.
PLoS One. 2023 Sep 14;18(9):e0290660. doi: 10.1371/journal.pone.0290660. eCollection 2023.
In this experiment, we took reflux sludge, sludge from an aeration tank, and soil from roots as microbial inoculating sources for an electrochemical device for denitrification with high-throughput sequencing on cathodic biofilms. The efficiency of nitrate nitrogen removal using different microbial inoculates varied among voltages. The optimal voltages for denitrification of reflux sludge, aeration tank sludge, and root soil were 0.7V, 0.5V, and 0.5V, respectively. Further analysis revealed that the respective voltages had a significant effect upon microbial growth from the respective inoculates. Proteobacteria and Firmicutes were the main denitrifying microbes. With the addition of low current (produced by the applied voltage), the Chao1, Shannon and Simpson indexes of the diversity of microorganisms in soil inoculation sources increased, indicating that low current can increase the diversity and richness of the microorganisms, while the reflux sludge and aeration tank sludge showed different changes. Low-current stimulation decreased microbial diversity to a certain extent. Pseudomonas showed a trend of decline with increasing applied voltage, in which the MEC (microbial electrolysis cell) of rhizosphere soil as inoculates decreased most significantly from 77.05% to 12.58%, while the MEC of Fusibacter showed a significant increase, and the sludge of reflux sludge, aeration tank and rhizosphere soil increased by 31.12%, 18.7% and 34.6%, respectively. The applied voltage also significantly increased the abundance of Azoarcus in communities from the respective inoculates.
在本实验中，我们采用回流污泥、曝气池污泥和根系土壤作为微生物接种源，通过高通量测序对阴极生物膜进行了用于高效脱氮的电化学装置实验。不同微生物接种源对硝酸盐氮去除的效率因电压而异。回流污泥、曝气池污泥和根土的最佳脱氮电压分别为 0.7V、0.5V 和 0.5V。进一步分析表明，各自的电压对来自各自接种源的微生物生长有显著影响。变形菌门和厚壁菌门是主要的脱氮微生物。随着低电流（由施加的电压产生）的加入，土壤接种源中微生物多样性的 Chao1、Shannon 和 Simpson 指数增加，表明低电流可以增加微生物的多样性和丰富度，而回流污泥和曝气池污泥则表现出不同的变化。低电流刺激在一定程度上降低了微生物的多样性。假单胞菌随着施加电压的增加呈下降趋势，其中以根际土壤为接种源的 MEC（微生物电解池）下降最为显著，从 77.05%降至 12.58%，而 Fusibacter 的 MEC 则显著增加，回流污泥、曝气池和根际土壤的 MEC 分别增加了 31.12%、18.7%和 34.6%。施加电压还显著增加了各接种源群落中偶氮arcus 的丰度。
