[Baterial ecology of electric-field composting: community structures, networks, and phenotypes].

内容摘要

To address the delayed heating and insufficient thermophilic phase caused by early mass transfer limitations and local oxygen shortage in aerobic composting, this study investigated the impacts of electric field intervention on the microbial ecological network and functional phenotypes. Composting experiments were conducted in 30 L reactors under different electric field intensities (0 V, 2 V, and 5 V). Physicochemical measurements, 16S rRNA-based community profiling, co-occurrence network analysis, and BugBase phenotype predictions were integrated to elucidate the coupling mechanism of electric field-microorganisms-process. The results demonstrated that electric field application markedly accelerated temperature rise and extended the thermophilic phase, with early-stage current dynamics tightly coupled to temperature. Although temporal succession remained the primary driver of microbial community structure, electric field treatments exerted significant additional effects, resulting in distinct community structures on days 7 and 18. At the genus level, electric field application enriched key taxa associated with electron transfer and fermentation (e.g., Pseudomonas, Proteiniphilum, Bacteroides, Methanocorpusculum, and Peptococcus). The network structure shifted from a "low-aggregation, short-path" pattern to a "high-aggregation, long-path" configuration, with the electric field reshaping the module affiliations and roles of dominant taxa and connectors. Weak fields promoted cross-module cooperation, whereas strong fields enhanced module compartmentalization and hub connectivity. The phenotypic level of BugBase showed periodic migration, and the 5-V electric field reshaped the bacteria to predict the phenotype spectrum effect stronger and earlier. The electric field treatment group was more inclined to enrich the phenotypes of aerobic bacteria, Gram-negative bacteria, biofilm formation, and stress tolerance, while tending to decrease Gram-positive phenotype. Collectively, the electric field enhanced microscale mass transfer and electron acceptor availability, thereby intensifying early metabolic and exothermic processes and restructuring the microbial network, achieving a state of acceleration without directional change. This study elucidates the microbial ecological mechanisms underlying electric-field regulation of aerobic composting, thereby providing a theoretical basis and technical framework for physical-field-enabled, precision modulation of microbial community functions and for the targeted optimization of composting processes. 为缓解好氧堆肥早期传质受限与局部缺氧导致的升温滞后与高温期不足，厘清电场介入对微生物生态网络与功能表型的影响，本研究设置不同强度(0 V、2 V、5 V)的电场施加于30 L反应器的堆肥过程，结合理化指标、16S rRNA细菌群落结构分析、共现网络与BugBase表型预测，解析电场堆肥下微生物群落组成与功能演替机制。研究结果显示:电场能够显著加速升温并延长高温期，前期电流与温度呈紧密耦合;堆肥时间是细菌群落结构的主要影响因素，但在控制时间后，电场效应依旧显著，且在第7天和第18天形成了显著分化的群落结构。属水平上，电场富集了与电子转移/发酵相关的关键类群，例如假单胞菌属(Pseudomonas)、嗜蛋白质菌属(Proteiniphilum)、拟杆菌属(Bacteroides)、甲烷粒菌属(Methanocorpusculum)、消化球菌属(Peptococcus)等，富集了发酵菌和电活性菌;网络结构由“低聚集、短路径”重组为“高聚集、长路径”，电场改变了优势菌与连接者的模块归属和相对位置，弱电场增强跨模块协同，强电场强化模块分区与枢纽连接。BugBase表型层面呈现阶段性迁移，且5 V电场对细菌表型谱的调控效应更强、更早出现。电场处理组更倾向于富集需氧型、革兰氏阴性、生物膜形成与应激耐受等表型，同时革兰氏阳性表型倾向降低。综上，电场通过改善微尺度传质与电子受体可用性，放大了前期代谢与放热过程，微生物网络结构重组，实现了“加速而不改向”。本研究阐明了电场调控好氧堆肥进程的微生物生态学机制，为通过物理场精准调控菌群功能、定向优化堆肥工艺提供了新的理论与技术路径。.