Valorization of food waste into hydroxymethylfurfural: Dual role of metal ions in successive conversion steps

Iris K.M. Yu, Daniel C.W. Tsang, Alex C.K. Yip, Season S. Chen, Yong Sik Ok, Chi Sun Poon

Research output: Contribution to journalArticlepeer-review

99 Citations (Scopus)


This study aimed to transform food waste into a value-added chemical, hydroxymethylfurfural (HMF), and unravel the tangled effects induced by the metal catalysts on each single step of the successive conversion pathway. The results showed that using cooked rice and bread crust as surrogates of starch-rich food waste, yields of 8.1–9.5% HMF and 44.2–64.8% glucose were achieved over SnCl4 catalyst. Protons released from metal hydrolysis and acidic by-products rendered Brønsted acidity to catalyze fructose dehydration and hydrolysis of glycosidic bond. Lewis acid site of metals could facilitate both fructose dehydration and glucose isomerization via promoting the rate-limiting internal hydride shift, with the catalytic activity determined by its electronegativity, electron configuration, and charge density. Lewis acid site of a higher valence also enhanced hydrolysis of polysaccharide. However, the metals also catalyzed undesirable polymerization possibly by polarizing the carbonyl groups of sugars and derivatives, which should be minimized by process optimization.

Original languageEnglish
Pages (from-to)338-347
Number of pages10
JournalBioresource technology
Publication statusPublished - 2016 Nov 1
Externally publishedYes

Bibliographical note

Funding Information:
The authors appreciate the financial support from the Hong Kong International Airport Environmental Fund , and the provision of food waste by South China Resources Reborn Co. Ltd. for this study.

Publisher Copyright:
© 2016 Elsevier Ltd


  • Biomass conversion
  • Bread/rice
  • Homogeneous catalysis
  • Lewis acid
  • Metal chloride

ASJC Scopus subject areas

  • Bioengineering
  • Environmental Engineering
  • Renewable Energy, Sustainability and the Environment
  • Waste Management and Disposal


Dive into the research topics of 'Valorization of food waste into hydroxymethylfurfural: Dual role of metal ions in successive conversion steps'. Together they form a unique fingerprint.

Cite this