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. 2021 Apr 4;18(7):3772.
doi: 10.3390/ijerph18073772.

Improvement of Enzymatic Glucose Conversion from Chestnut Shells through Optimization of KOH Pretreatment

Kang Hyun Lee  1 , Soo Kweon Lee  2 , Jeongho Lee  1 , Seunghee Kim  1 , Chulhwan Park  3 , Seung Wook Kim  2 , Hah Young Yoo  1
Affiliations

Improvement of Enzymatic Glucose Conversion from Chestnut Shells through Optimization of KOH Pretreatment

Kang Hyun Lee et al. Int J Environ Res Public Health. .

Abstract

Worldwide, about one-third of food produced for human consumption is wasted, which includes byproducts from food processing, with a significant portion of the waste still being landfilled. The aim of this study is to convert chestnut shells (CNSs) from food processing into a valuable resource through bioprocesses. Currently, one of the highest barriers to bioprocess commercialization is low conversion of sugar from biomass, and KOH pretreatment was suggested to improve enzymatic digestibility (ED) of CNS. KOH concentration of 3% (w/w) was determined as a suitable pretreatment solution by a fundamental experiment. The reaction factors including temperature, time and solid/liquid (S/L) ratio were optimized (77.1 g/L CNS loading at 75 °C for 2.8 h) by response surface methodology (RSM). In the statistical model, temperature and time showed a relatively significant effect on the glucan content (GC) and ED, but S/L ratio was not. GC and ED of the untreated CNS were 45.1% and 12.7%, respectively. On the other hand, GC and ED of pretreated CNS were 83.2% and 48.4%, respectively, and which were significantly improved by about 1.8-fold and 3.8-fold compared to the control group. The improved ED through the optimization is expected to contribute to increasing the value of byproducts generated in food processing.

Keywords: KOH pretreatment; chestnut shells; enzymatic hydrolysis; food processing wastes; statistical optimization.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Effect of KOH pretreatment of chestnut shells (CNSs) on chemical composition (a) and the released glucose concentrations after the enzymatic hydrolysis (b).
Figure 2
Figure 2
The three-dimensional response surface plot for the interactive effect of temperature and time (a), temperature and S/L ratio (b) and time and S/L ratio (c) on glucan content (GC).
Figure 2
Figure 2
The three-dimensional response surface plot for the interactive effect of temperature and time (a), temperature and S/L ratio (b) and time and S/L ratio (c) on glucan content (GC).
Figure 3
Figure 3
The three-dimensional response surface plot for the interactive effect of temperature and time (a), temperature and S/L ratio (b) and time and S/L ratio (c) on enzymatic digestibility (ED).
Figure 3
Figure 3
The three-dimensional response surface plot for the interactive effect of temperature and time (a), temperature and S/L ratio (b) and time and S/L ratio (c) on enzymatic digestibility (ED).
See this image and copyright information in PMC

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