Abstract Efficient and sustainable pretreatment is critical for improving fermentable sugar yields from lignocellulosic biomass. Biomass was subjected to two pretreatment approaches using choline chloride:glycerol (1:2), followed by dilute acid hydrolysis (1.99% H 2 SO 4 , 121 °C, 1 min). The effects of temperature or microwave power, treatment time, and liquid‐to‐solid ratio (LSR) were evaluated using response surface methodology to determine optimal conditions. Microwave pretreatment (460 W, 64.8 s, LSR 9.90 w/w) yielded 69.31 g L −1 fermentable sugar content (FSC), corresponding to 0.61 g fermentable carbohydrate per gram of untreated barley husks. The temperature‐controlled reactor (TCR) achieved optimal conditions at 101.32 °C, 37.42 min, and LSR 4 w/w, yielding 47.93 g L −1 FSC and 0.40 g g −1 fermentable carbohydrate per g of untreated barley husks. The hydrolysates exhibited distinct sugar profiles. The TCR produced mainly xylose and fructose, with sucrose and maltose undetected. Microwave pretreatment produced higher glucose levels alongside xylose and fructose. Microwave pretreatment also reduced inhibitory compounds, including 5‐hydroxymethylfurfural (HMF) and furfural. Both approaches suppressed benzoic acid formation through effective delignification and modified the chemical composition of barley husks by reducing extractives and lignin while improving cellulose availability. Microwave‐assisted deep eutectic solvent pretreatment required a shorter processing time, produced a higher sugar yield, and reduced inhibitor formation. The results suggest that deep eutectic solvent (DES)‐based microwave pretreatment is a promising and selective strategy for the valorization of barley husks as a lignocellulosic feedstock.
Yavuz et al. (Sun,) studied this question.