Unveiling methane oxidation dynamics, microbial community, and function of Fe(III)-driven anaerobic methane oxidation inside landfill

Trivalent iron (Fe³⁺) could participate in methane (CH₄) oxidation as an electron acceptor under anaerobic conditions, but the kinetic process remains unknown in landfills, and the understanding of metabolic pathway of Fe³⁺-dependent anaerobic methane oxidation (Fe-DAMO) is still limited. In this study, the dual-substrate (CH₄-Fe³⁺) kinetic model of CH₄ oxidation is obtained with V_max (7.35 ± 0.4184)μmol/(kg d), half-saturation constant \({K}_{m,{CH}_{4}}\) $K_{m,{\mathit{CH}}_4}$ (16.6699 ± 2.3940)ppmv, and \({K}_{m,{Fe}^{3+}}\) $K_{m,{\mathit{Fe}}^{3+}}$ (0.00107 ± 0.0002g/g). Microbial community analysis shows that Methanobacteriales and Clostridia are dominant microorganisms of Fe-DAMO. PICRUSt analysis confirms that the metabolic pathway of AMO is the reverse CH₄ production pathway. The results provide a new perspective for CH₄ biodegradation in landfills and offer a better understanding of Fe-DAMO process.