Upgrading lignocellulosic ethanol for caproate production via chain elongation fermentation

Peixian Yang, Ling Leng, Giin Yu Amy Tan, Chengyu Dong, Shao Yuan Leu, Wen Hsing Chen, Po Heng Lee

Research output: Journal article publicationJournal articleAcademic researchpeer-review

12 Citations (Scopus)


Chain elongation is a promising mixed culture bioprocess to convert acetate into medium chain carboxylates with ethanol as an electron donor. Caproate production using lignocellulosic ethanol (LE) as feedstock via chain elongation fermentation was examined in this study. Meanwhile, the effects of yeast extract and cellulose containing in the LE were investigated separately. Fermentation performance showed that the lag phase of caproate production were shortened in experimental group LE (4 days), yeast extract (6 days), and cellulose (9 days) compared with the control group (17 days) without extra supplement. The insufficiency of electron donor, ethanol, limited further elongation into caproate, resulting in comparable caproate yields and carbon conversion ratios in four experimental groups. Microbial community and microbial kinetics analysis revealed that yeast extract could be metabolized by protein-utilizing bacteria into short chain carboxylates (SCCs), which facilitated biological chain elongation. Meanwhile, yeast extract boosted microbial growth by serving as nitrogen and other nutrient sources. Furthermore, cellulose was utilized and further converted into SCCs, or even caproate, by cellulolytic bacteria. Together, caproate production was enhanced with high microbial activities and intermediates formation using LE. This study upgrades LE into a higher energy density product, caproate, via the energy-efficient chain elongation fermentation.

Original languageEnglish
Pages (from-to)103-109
Number of pages7
JournalInternational Biodeterioration and Biodegradation
Publication statusPublished - Nov 2018


  • Anaerobic fermentation
  • Caproate production
  • Carboxylates chain elongation
  • Lignocellulosic ethanol
  • Microbial community
  • Microbial kinetics

ASJC Scopus subject areas

  • Microbiology
  • Biomaterials
  • Waste Management and Disposal

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