Microbe-iron interactions control lignin decomposition in soil

Cuijuan Liao, Wenjuan Huang, Jon Wells, Ruiying Zhao, Keanan Allen, Enqing Hou, Xin Huang, Han Qiu, Feng Tao, Lifen Jiang, Maricar Aguilos, Lin Lin, Xiaomeng Huang, Yiqi Luo

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Lignin decomposition is critically linked to terrestrial carbon (C) cycle due to the enormous C mass of lignin and its importance in controlling overall rates of litter decomposition. Interactions between lignin and iron (Fe) minerals have been increasingly recognized as key mediators of lignin decomposition in experimental studies. However, we still lack a quantitative understanding of how Fe minerals interact with microbes to control lignin decomposition. Here, we leveraged experimental results from an incubation of Fe-rich soil, in which lignin decomposition rates were measured at aerobic conditions after four levels of pre-treated O2 availability, to examine microbe-Fe (MiFe) interactions in lignin decomposition with a MiFe model. We quantified how Fe redox cycling interacted with microbial activities to control lignin decomposition via data-model integration. Our results showed that the MiFe model with time-dependent growth and mortality functions better represented CO2 release from lignin decomposition (R2 ranging from 0.96 to 0.97) than models assuming either first-order or Michaelis-Menten kinetics. Reduction of Fe(III) to Fe(II) after pre-treatments with lower O2 availability stimulated the Fenton reaction to break down macro-molecular lignin into small molecules available to microbes. The small molecules of lignin and necromass bounded with oxidized Fe and were protected from decomposition. After 1-year incubation, the model implied that most of C stabilized with Fe minerals was derived from small molecular lignin C. Our quantitative analysis of microbe-Fe interactions sheds new light on lignin decomposition and preservation and helps improve model prediction of soil C persistence under global change.

Original languageEnglish (US)
Article number108803
JournalSoil Biology and Biochemistry
StatePublished - Oct 2022
Externally publishedYes


  • Data assimilation
  • Iron redox
  • Lignin decomposition
  • Microbial model
  • Mineral associated organic matters

ASJC Scopus subject areas

  • Microbiology
  • Soil Science


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