以底物浓度为调控因子探究MFC-MEC性能与微生物群落之间的关系

Relationship between MFC-MEC performance and microbial community with substrate concentration as a regulatory factor

摘要:

背景 底物浓度是调控生物电化学系统(bioelectrochemical systems, BES)生物膜微生物群落的关键环境因子，而微生物群落结构则主导BES的性能。然而，底物浓度、功能菌群与系统之间的关系仍然不清楚。目的 探究阳极生物膜中微生物群落结构与系统性能之间的关系。方法 基于微生物燃料电池(microbial fuel cells, MFC)与微生物电解池(microbial electrolysis cells, MEC)耦合的共用阳极(share anode-microbial fuel cell, SA-MFC)和共用阴极(share cathode-microbial fuel cell, SC-MFC)生物能源耦合系统，以底物浓度为调控因子，通过监测电化学参数，并利用16S rRNA基因测序技术得到微生物群落结构与系统性能之间的关系。结果 在SA-MFC中，底物浓度为2 g/L时性能最优，最大功率密度达500.72 mW/m²，相较1 g/L时提升1倍；在SC-MFC中，最优底物浓度为3 g/L，最大功率密度为52.13 mW/m²，相较1 g/L时提高0.3倍，表明底物浓度显著影响系统产电性能。从微生物群落结构来看，产电性能的提升与特定功能菌群的富集密切相关，如产甲烷菌[甲烷八叠球菌属(Methanosarcina)，甲烷鬃毛状菌属(Methanosaeta)]、硫循环相关菌[硫杆菌属(Thiobacillus),硫卵菌属(Sulfurovum)]及发酵菌嗜蛋白质菌属(Proteiniphilum)等。这些菌群通过促进胞外聚合物的合成和优化电子传递效率等方式提高系统的产电性能。结论 通过调控底物浓度可实现功能菌群的有效富集，为优化BES的运行参数提供了基础。

Abstract:

Background Substrate concentration is a key environmental factor that regulates the microbial community of biofilms in bioelectrochemical systems (BES), while the microbial community structure dominates the performance of BES. However, the relationship between substrate concentration, functional flora, and the system remains unclear.Objective To investigate the relationship between the microbial community structure in the anodic biofilm and the performance of the system.Methods To this end, a bioenergy coupling system based on the coupling of microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) was studied, featuring a shared anode (SA-MFC) and a shared cathode (SC-MFC). Taking substrate concentration as the regulatory factor, the relationship between microbial community structure and system performance in the anode biofilm and system performance was investigated by monitoring electrochemical parameters and utilizing 16S rRNA gene sequencing technology.Results In SA-MFC, the performance was optimal at a substrate concentration of 2 g/L, with a maximum power density of 500.72 mW/m², which was double that at 1 g/L. In SC-MFC, the optimal substrate concentration was 3 g/L, yielding a maximum power density of 52.13 mW/m², which was 0.3 times higher than that of 1 g/L. This indicates that substrate concentration significantly affects the power generation performance of the system. From the perspective of microbial community structure, the improvement in power production performance was closely related to the enrichment of specific functional flora, such as methanogens (Methanosarcina, Methanosaeta), sulfur cycle-related bacteria (Thiobacillus, Sulfurovum), and fermentation bacteria (Proteiniphilum). These flora improve the power generation performance of the system by promoting the synthesis of extracellular polymers (EPS) and optimizing electron transport efficiency.Conclusion The effective enrichment of functional flora can be achieved by regulating the substrate concentration, providing a basis for optimizing operating parameters of the bioelectrochemical system.