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

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.

Microbial Production of Bacterial Cellulose Using Chestnut Shell Hydrolysates by Gluconacetobacter xylinus ATCC 53524

“…Acetic acid is produced specifically when the acetyl group of hemicellulose is released during this enzymatic saccharification process [ 20 ]. CS contains 2.4–5.9% (w/w) of hemicellulose, as previously reported [ 21 ]. Thus, residual acetyl groups in hemicellulose may have been released from the CS during enzymatic saccharification.…”

Cellulosic Butanol Biorefinery: Production of Biobutanol from High Solid Loadings of Sweet Sorghum Bagasse—Simultaneous Saccharification, Fermentation, and Product Recovery

“…This resulted in total sugar utilization of 28.07 gL −1 for acid production, cell growth, and maintenance energy, thus leaving behind 71.39 gL −1 (99.46 gL −1 (total sugar for conversion) − 28.07 gL −1 (cell growth, acid production, and maintenance)) sugar for ABE production. Based on a theoretical ABE yield of 0.39 [23], the culture produced 27.84 gL −1 ABE. Since it was a closed system (no bleed), the only way ABE could leave was either by diffusion through the rubber tubing or with the exit gas.…”

Enhanced Production of Bacterial Cellulose from Miscanthus as Sustainable Feedstock through Statistical Optimization of Culture Conditions

“…Various studies have investigated the utilization of biomass as a carbon source [ 8 , 10 , 17 ]. The use of conventional biomass from sources such as corn, wheat, and sugar cane for use as a carbon source entails food-related ethical issues [ 8 , 18 ]. In contrast, the use of Miscanthus does not impact food security and has several advantages such as high biomass yields per unit of arable land, the ability to grow easily without requiring pesticides or fertilizers, and a long lifespan [ 8 , 19 ].…”