Perspectives on Potential Applications of Nanometal Derivatives in Gaseous Bioenergy Pathways: Mechanisms, Life Cycle, and Toxicity

Mohamed Elsamadony*, Ahmed Elreedy, Alsayed Mostafa, Manabu Fujii, Johannes Gescher, Sepehr Shakeri Yekta, Anna Schnürer, Jean François Gaillard, Deepak Pant

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

12 Scopus citations


Nanosized metal derivatives (NMDs), referring to metals and their oxides, are extensively utilized as additives for anaerobic digestion (AD) and dark fermentation (DF) processes, for enhancing the production of methane (CH4) and hydrogen (H2), respectively. NMDs-derived positive impacts were widely confirmed in many previous studies; however, no consensus exists about how these have been acquired. Undoubtedly, NMDs affect extracellular electron transfer (EET). Consequently, we explore how biotic-biotic interactions, referring to direct interspecies electron transfer (DIET) among AD partners, and biotic-abiotic exchanges, which are mediated by redox reactions with metals, are affected. In this perspective, the mechanisms behind all those effects are reviewed and explained in detail, considering the specific properties of each NMD, e.g., size and type. We discuss previous studies that offer contradicting interpretations about which process dominates metal oxidation, metal reduction, or DIET. In addition, the fate of NMDs residues in the digestate after the treatment process is discussed, focusing on NMDs toxicity. From previous literature, the environmental impacts are evaluated for the production process of NMDs that are utilized in AD and DF processes via life-cycle assessment. This review provides a comprehensive understanding of NMDs-microbes interactions, which are mandatory for (i) building clear scientific knowledge about processes in play and (ii) engineering favorable conditions to achieve optimum yields in AD and DF processes.

Original languageEnglish (US)
Pages (from-to)9563-9589
Number of pages27
JournalACS Sustainable Chemistry and Engineering
Issue number29
StatePublished - Jul 26 2021


  • Direct interspecies electron transfer (DIET)
  • Dissimilatory metal reduction
  • Lifecycle assessment
  • Metal corrosion
  • Nanoparticle
  • Toxicity

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment


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