Akademik Veri Yönetim Sistemi
Biomass Conversion and Biorefinery, 2023 (SCI-Expanded)
In the present work, a systematic study has been performed to optimize the pretreatment of lignocellulosic biomass (wheat bran (WB)) to maximize fermentable sugar content by using an effective combination of high-pressure and deep eutectic solvents (DES). First, DES type and molar ratios were compared to determine the most suitable condition for the pretreatment at high-pressure reactor (HPR). This was performed with a two-stage pretreatment. WB samples were mixed with choline chloride (ChCl):glycerol and ChCl:acetic acid at different molar ratios (1:2, 1:4, and 1:6) and treated at 80 °C for 24 h in a water bath (conventional DES treatment). Then, DES-applied biomass was mixed with 1.99% (v/v) sulphuric acid solution at 121 °C in an autoclave for 1 min. ChCl:glycerol (1:2 molar ratio) and ChCl:acetic acid (1:2 molar ratio) provided the highest fermentable sugar concentrations (FSCs), 72.54 and 69.77 g/L, respectively. Therefore, the experiments in the high-pressure reactor (HPR) were continued with the aforementioned DES types. The effects of temperature (T, 100–150 °C), time (t, 20–40 min) and liquid-to-solid ratio (LSR, 4–10 w/w) on the FSCs in the HPR were examined using Box–Behnken Design (BBD) of response surface methodology (RSM). FSC and total phenolic substance concentration (TPC) were selected as dependent variables. In addition, the levels of sugars (glucose, xylose, fructose, sucrose, maltose and arabinose) and furans (furfural and 5-hydroxymethylfurfural (HMF)) in the samples were also measured after the pretreatment. Based on the results, the optimal pretreatment conditions were found as 130 °C, 27 min and 4 w/w liquid-to-solid ratio with ChCl: glycerol (1:2). Under optimal conditions, FSC and TPC were 75.43 g/L and 0.41 g GA/L. The results showed that DES pretreatment in the HPR is a promising technology that can be successfully implemented for the pretreatment of lignocellulosic biomass resulting in high sugar yields.