Microwave-assisted low-temperature hydrothermal treatment of red seaweed (Gracilaria lemaneiformis) for production of levulinic acid and algae hydrochar

Leichang Cao, Iris K.M. Yu, Dong Wan Cho, Di Wang, Daniel C.W. Tsang, Shicheng Zhang, Shiming Ding, Linling Wang, Yong Sik Ok

Research output: Journal article publicationJournal articleAcademic researchpeer-review

84 Citations (Scopus)


In this study, red seaweed (Gracilaria lemaneiformis) food waste with high carbohydrate content was valorized into levulinic acid (LA) and algae hydrochar through microwave-assisted low-temperature hydrothermal treatment in dilute acid solution. Various parameters including treatment temperature (160–200 °C), reaction time (1–40 min), acid concentration (0–0.6 M), and biomass-to-liquid ratio (1%–10%, w/v) were examined. The energy efficiency and carbon recovery of the proposed process were investigated. Under the experimental conditions of 5% (w/v) biomass loading, 0.2 M H2SO4, 180 °C, and 20 min, the highest levulinic acid yield of 16.3 wt% was produced. The resulting hydrochar showed approximately 45–55% energy yield and higher heating values of 19–25 MJ kg−1. The energy efficiency of the present study (1.31 × 10−6 g LA/J) was comparable to those of the conventional hydrothermal treatment of lignocellulosic biomass, while the reaction time (20 min) was much shorter with a high carbon recovery (73.3%).

Original languageEnglish
Pages (from-to)251-258
Number of pages8
JournalBioresource Technology
Publication statusPublished - Feb 2019


  • Acid hydrolysis
  • Carbohydrate-rich biomass
  • Engineered biochar
  • Food waste valorization
  • Macroalgae biorefinery

ASJC Scopus subject areas

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

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