Detection of organic carbon sequestration in typical brown soil by different microbial functional groups based on electrochemical detection

This study investigates the use of an organic functional microbial consortium for soil bioremediation and the stabilization of embolized soil organic carbon (SOC). Metagenomic sequencing and qPCR were employed to characterize key microbial groups, including decomposers, methanogens, nitrate-reducing bacteria, and fungi. Electrochemical techniques—cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA)—were applied to evaluate how microbial activity influences heterogeneous electron transfer during SOC sequestration. Partial least squares regression (PLSR) was used to assess relationships between microbial metabolism and electrochemical indicators. Increased CV peak currents and reduced EIS resistance reflected heightened microbial activity and improved SOC retention. Forest soils showed the highest SOC content (3.5 ± 0.3%), lowest impedance (120 Ω), and highest CV peak current (≈45 µA), indicating superior microbial transfer efficiency and SOC stabilization. The PLSR model demonstrated strong predictive power for microbial electrochemical activity and SOC sequestration (R² = 0.89; p < 0.01). Overall, the findings support the use of electrochemical proxies to quantify microbial contributions to SOC retention and to predict SOC dynamics in real time. Future work should focus on enhancing electrochemical sensitivity through advanced molecular tools to improve mechanistic understanding of SOC stabilization.