| F/M对活性污泥微生物生态网络的影响 |
| 摘要点击 2988 全文点击 948 投稿时间：2021-07-12 修订日期：2021-08-05 |
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| 中文关键词 活性污泥(AS) 微生物群落 有机负荷率 (F/M) 生态网络 关键物种 |
| 英文关键词 activated sludge(AS) microbial community food to microorganism ratio(F/M) network keystone |
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| 中文摘要 |
| 为深入理解有机负荷率（F/M）对活性污泥（AS）微生物群落的影响，以F/M（以BOD/MLVSS计，下同）设计建议范围0.2~0.5 kg·（kg·d）-1为依据，将采集的AS样品分为3组，运用基于随机矩阵理论（RMT）的网络分析方法，解析了不同F/M条件下的AS微生物生态网络拓扑性质及结构特征.结果表明，较低的F/M能够显著降低AS微生物群落的多样性和均匀度，但较高的F/M未对群落多样性和均匀度产生显著影响，表明多样性指标对高F/M不敏感.不同F/M条件下微生物生态网络均具有无标度、小世界和模块化的特征，但F/M较高或较低均会降低网络的规模及复杂度.当F/M在0.2~0.5 kg·（kg·d）-1范围内，生态网络具有最多的总节点数、最大的平均聚集系数以及最小的平均路径距离；此时的网络规模最大，网络复杂度最高，AS群落的结构和功能也因此最为稳定.不同F/M条件下AS微生物间的正负相互作用关系也存在差异：其中F/M较低时，网络中节点的正连接比例为71.1%；当F/M在0.2~0.5 kg·（kg·d）-1时，微生物间的正相关关系最多，为76.8%；当F/M超过0.5 kg·（kg·d）-1时，正相关关系降至60.0%.此外，F/M在0.2~0.5 kg·（kg·d）-1时网络识别出了24个关键物种，而F/M低于0.2 kg·（kg·d）-1和高于0.5 kg·（kg·d）-1时，网络仅识别出4个和7个关键物种.上述性质均表明F/M在0.2~0.5 kg·（kg·d）-1范围内，AS微生物可能会更高效地进行物质传输和利用，同时抵御环境扰动的能力也更强，群落稳定性更高. |
| 英文摘要 |
| The performance of wastewater treatment plants (WWTPs) mainly relies on the microbial community in activated sludge (AS). The food to microorganisms (F/M) ratio is an important operational parameter, the recommended value of which is between 0.2 and 0.5 kg·(kg·d)-1. The F/M directly influences microbial growth and metabolism, but how the F/M ratio affects AS microbial networks and the related mechanisms remain unclear. In this study, 63 AS samples with different F/M ratios were analyzed by utilizing a random-matrix-theory based network pipeline. Firstly, all 63 samples were divided into three groups based on their F/M ratios (lower F/M group, normal F/M group, and higher F/M group). The results indicated that the lower F/M decreased microbial diversity and evenness significantly, but the higher F/M had no significant effects on the diversity of the microbial community. All three constructed networks were scale-free, small world, and modular, but network size and complexity were decreased in the lower and higher F/M groups. The network of the normal F/M ratio group was detected with the most nodes, the highest average clustering coefficient, and the shortest geodesic distance. The proportion of positive links was 76.8% when the F/M was within the normal range. On the contrary, 71.1% and 60.0% of positive links were identified when the F/M was below 0.2 and above 0.5 kg·(kg·d)-1. Moreover, 24 keystones were detected in the normal F/M network, whereas only 4 and 7 keystones were detected in the lower and higher F/M networks. Overall, our results provided clear evidence that the AS microbial community could be more stable and resilient to environmental disturbance when the F/M ratio was between 0.2 and 0.5 kg·(kg·d)-1. |
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