Energy-efficient glucose recovery from chestnut shell by optimization of NaOH pretreatment at room temperature and application to bioethanol production

Kang Hyun Lee, Soo Kweon Lee, Jeongho Lee, Seunghee Kim, Seung Wook Kim, Chulhwan Park, Hah Young Yoo

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15 Citations (Scopus)


Biofuel policies are currently being implemented globally to reduce greenhouse gas emissions. The recent European regulation, Renewable Energy Directive (RED) II, states that renewable resources should be used as raw materials. In this study, chestnut shell (CNS), a food processing residue, was utilized as a feedstock for bioethanol production. Statistical optimization was performed to improve biomass-to-glucose conversion (BtG) from the CNS. In order to design an energy-efficient process, the pretreatment was fixed at room temperature in the numerical optimization. The optimal conditions derived from the predicted model are as follows: temperature of 25 °C, reaction time of 2.8 h, and NaOH concentration of 1.9% (w/w). Under optimal conditions, both predicted and experimental BtG were 31.0%, while BtG was approximately 3.3-fold improved compared to the control group (without pretreatment). The recovered glucose was utilized for bioethanol fermentation by Saccharomyces cerevisiae K35 and the ethanol yield was achieved to be 98%. Finally, according to the mass balance based on 1000 g CNS, glucose of 310 g can be recovered by the pretreatment; the bioethanol production was approximately 155 g. This strategy suggests a direction to utilize CNS as a potential feedstock for biorefinery through the design of an economical and energy-efficient pretreatment process by lowering the reaction temperature to room temperature.

Original languageEnglish
Article number112710
JournalEnvironmental Research
Publication statusPublished - 2022 May 15

Bibliographical note

Funding Information:
This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Ministry of Science and ICT ( MSIT ) ( NRF-2020R1C1C1005060 and NRF-2020R1A2C1007493 ) and a research grant from KwangWoon University (2021) .

Publisher Copyright:
© 2022


  • Bioethanol production
  • Enzymatic hydrolysis
  • Food processing residue
  • NaOH pretreatment
  • Optimization

ASJC Scopus subject areas

  • Biochemistry
  • General Environmental Science


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