Generation of Reducing Sugars from Corncob by Magnetic Carbon-Based Solid Acid Pretreatment Combined with In Situ Enzymatic Hydrolysis

Abstract The efficient conversion of hemicellulose and cellulose in lignocellulosic biomass to reducing sugars remains as one major challenge for the development of biorefinery. In this work, corncob saccharification in the aqueous phase was realized efficiently via pretreatment by magnetic carbon-based solid acid (MMCSA) catalyst, combined with the subsequent in situ enzymatic hydrolysis (occurring in the same pretreatment system after MMCSA separation). Under the optimized pretreatment conditions (the ratio of corncob, catalyst and water is 1:1:20 (g:g:mL), 160°C for 20 min) and in situ enzymatic hydrolysis (cellulase loading of 20 FPU / g, 24 h), an xylose yield of 88.77% and an enzymatic digestibility of 91.24% were obtained, respectively. Compared with the traditional enzymatic process, the present in situ enzymatic system has advantages of reduced enzyme loading, water consumption, and improved saccharification efficiency. Thus, this study provides a more sustainable and effective method for the saccharification of hemicellulose and cellulose in the corncob to produce reducing sugars.