2,5-DMBQ (2,5-Dimethoxybenzoquinone) serves as an extracellular reductant. 2,5-DMBQ is involved in a crucial redox cycle, namely the extracellular hydroquinone-quinone redox cycle. In this cycle, 2,5-DMBQ is capable of reducing extracellular Fe^³⁺ and generating H₂O₂. 2,5-DMBQ plays a pivotal role in the biodegradation mechanism of brown rot fungal, assisting the fungi in decomposing and utilizing organic matter^[1][2].