Unravelling a microbial synergy to boost caproate production via carboxylates chain elongation with ethanol

Ling Leng, Ying Wang, Peixian Yang, Takashi Narihiro, Masaru Konishi Nobu, Amy Giin Yu Tan, Henry Po Heng Lee

Research output: Journal article publicationJournal articleAcademic researchpeer-review


Chain elongation of volatile fatty acids for medium chain fatty acids production (e.g. caproate) is an attractive approach to treat wastewater anaerobically and recover resource simultaneously. Undefined microbial consortia can be tailored to achieve chain elongation process with selective enrichment from anaerobic digestion sludge, which has advantages over pure culture approach for cost-efficient application. Whilst the metabolic pathway of the dominant caproate producer, Clostridium kluyveri, has been annotated, the role of other coexisting abundant microbiomes remained unclear. To this end, an ethanol-acetate fermentation inoculated with fresh digestion sludge at optimal conditions was conducted. Also, physiological study, thermodynamics and 16 S rRNA gene sequencing to elucidate the biological process by linking the system performance and dominant microbiomes were integrated. Results revealed a possible synergistic network in which C. kluyveri and three co-dominant species, Desulfovibrio vulgaris, Fusobacterium varium and Acetoanaerobium sticklandii coexisted. D. vulgaris and A. sticklandii (F. varium) were likely to boost the carboxylates chain elongation by stimulating ethanol oxidation and butyrate production through a syntrophic partnership with hydrogen (H2) serving as an electron messenger. This study unveils a synergistic microbial network to boost caproate production in mixed culture carboxylates chain elongation.

Original languageEnglish
Pages (from-to)63-71
Number of pages9
JournalHKIE Transactions Hong Kong Institution of Engineers
Issue number2
Publication statusPublished - Jun 2019


  • Caproate production
  • Carboxylates chain elongation
  • Lag phase reduction
  • Mixed culture
  • Synergistic network
  • Wastewater recovery

ASJC Scopus subject areas

  • Engineering(all)


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