Enhanced Enzymatic Hydrolysis of Corncob by Synthesized Enzyme-Mimetic Magnetic Solid Acid Pretreatment in an Aqueous Phase

Abstract

A novel magnetic carbon-based solid acid catalyst (C350-Cl) was synthesized through a simple impregnation–carbonization process and used for the pretreatment of corncob in an aqueous medium. Under the optimized pretreatment reaction conditions, the yield of pentose reached 91.6% with a hemicellulose removal rate of 91.7%, and the subsequent enzymatic digestibility of the pretreated corncob residue reached 90.0% at 48 h. C350-Cl is a magnetic enzyme-mimetic solid acid catalyst, and its catalytic behavior is similar to those of enzymes. In addition, the catalyst is also an excellent carrier for Fe and Cl in that the Fe3+ and Cl–can be released slowly in the pretreatment to assist the hydrolysis of lignocellulose. Compared with the traditional method with other catalysts, this hydrolysis process is suitable for the effective and sustainable saccharification of lignocellulose for producing fermentable sugar.

Synthesis of a Stable Solid Acid Catalyst from Chloromethyl Polystyrene through a Simple Sulfonation for Pretreatment of Lignocellulose in Aqueous Solution

“…The procedure of using the wet residue as the feedstock for enzymatic hydrolysis has obvious advantages, like simplifying the operation and saving water consumption, which is more suitable for the industrial utilization. In summary, the enzymatic digestibility of the SCPR140‐1‐pretreated residue and the glucose concentration obtained during the enzymatic hydrolysis, no matter whether it was wet, or washed and dried, is comparable to the residue pretreated by other methods [37,54] …”

“…When the reaction temperature was above 150 °C (compare 150 and 160 °C), the yields of xylose increased in the first 30 min, and then decreased with time continuously prolonged. These results imply that the increase in reaction temperature could not only promote the conversion of hemicellulose or xylan into xylose, but also accelerate the degradation of xylose into other products [37] . When the reaction temperature was above 150 °C, the formation rate of xylose was much lower than the xylose degradation rate, leading to a decrease in the xylose yield [38] .…”

“…We analyzed the reason for the slight decrease of xylose yield from 73.07 to 69.49 % when the catalyst was reused for the first time. As shown in Figure 9, it can be seen that the total acid content decreases from initial amount of 3.12 to 2.56 mmol g −1 after the first use, which will affect the catalytic activity of SCPR140‐1 [37] . From the analysis of supernatant from hydrothermal treatment of SCPR140‐1 (Table 2), it was found that the SO 4 2− ion concentration in the supernatant was 0.0012 mol L −1 after the first use of SCPR140‐1.…”

A hemicellulose-first approach: one-step conversion of sugarcane bagasse to xylooligosaccharides over activated carbon modified with tandem plasma and acid treatments

“…Consequently, the total yield decreases. 40 AC is resistant to heat and chemicals, so a high dose of catalyst will protect the substrate from the effects of high temperatures and solvents.…”

“…These functional groups result in enhanced adsorption between the catalyst and the biomass, allowing for the cleavage of the glycosidic bonds. 40 The formation of xylose is due to the long reaction time due to the degradation of XOS. No sugar degradation products of furfural, HMF, and levulinic acid were detected, except for traces of formic acid (below detection limit).…”