1 School of Environmental and Municipal Engineering, Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Chengjian University, Jinjing Road 26, Tianjin 300384, China.
2 School of Civil Engineering and Architecture, Taizhou University, Taizhou 318000, China.
3 Department of Building, Civil, and Environmental Engineering, Concordia University, 1455 de Maisonneuve Blvd. W. Montreal, Quebec, Canada.
4 School of Civil Engineering and Architecture, Taizhou University, Taizhou 318000, China. Electronic address: wangxiaoping624@163.com.
5 School of Civil Engineering and Architecture, Taizhou University, Taizhou 318000, China. Electronic address: jianbguo@163.com.

A novel functional nanomaterial composed of guanosine monophosphate (GMP) and Fe enhanced denitrification efficiency by regulating electron transfer and microbial community. Fe/GMP enhanced nitrate (NO₃^-) degradation rates by 3.00-fold in serum vial batch experiments, with a rate constant of 17.39 mg/(L·h) in sequencing batch reactor. Fe/GMP-mediated interface promoted the secretion of redox-active substances in the extracellular polymeric substances to enhance the extracellular electron transfer. Specifically, Fe/GMP regulated electron transfer and metabolism activity by dynamic conversion of Fe³⁺/Fe²⁺ redox signal. Additionally, enzyme activity assays verified the optimized electron distribution function of Fe/GMP and thus enhanced intracellular electron transfer. High-throughput sequencing confirmed Fe/GMP selectively enriched microorganisms (especially Thauera 50.70 %). The tetraethylammonium stress experiment demonstrated Fe/GMP as an exogenous signaling molecule to restore microbial communication for microbial community regulation. The study proposes a multifaceted synergistic mechanism based on the repeater function of Fe/GMP in denitrification and offers insights for practical applications.