The Bioaugmentation of Electroactive Microorganisms Enhances Anaerobic Digestion

Zheng Kai An, Young Chae Song, Keug Tae Kim, Chae Young Lee, Seong Ho Jang, Byung Uk Bae

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Direct interspecies electron transfer (DIET) between electroactive microorganisms (EAMs) offers significant potential to enhance methane production, necessitating research for its practical implementation. This study investigated enhanced methane production through DIET in an anaerobic digester bio-augmented with EAMs. A horizontal anaerobic digester (HAD) operated for 430 days as a testbed to validate the benefits of bioaugmentation with EAMs. Anaerobic digestate slurry, discharged from the HAD, was enriched with EAMs in a bioelectrochemical auxiliary reactor (BEAR) under an electric field. This slurry enriched with EAMs was then recirculated into the HAD. Results showed bio-augmentation with EAMs led to an increase in volatile solids removal from 56.2% to 77.5%, methane production rate from 0.59 to 1.00 L/L.d, methane yield from 0.26 to 0.34 L/g CODr, and biogas methane content from 59.9% to 71.6%. It suggests that bio-augmentation enhances DIET, promoting the conversion of volatile fatty acids to methane and enhancing resilience against kinetic imbalances. The enrichment of EAMs reached optimal efficacy under an electric field intensity of 2.07 V/cm with a mean exposure time of 2.53 days to the electric field in the BEAR. Bio-augmentation with externally enriched EAMs is a feasible and effective strategy to optimize anaerobic digestion processes.

Original languageEnglish
Article number988
JournalFermentation
Volume9
Issue number11
DOIs
StatePublished - Nov 2023

Keywords

  • bioelectrochemical reactor
  • direct interspecies electron transfer
  • electric field
  • methanogenesis promotion
  • resilience of anaerobic digestion

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