Comparison of the effects of different pretreatments on the structure and enzymatic hydrolysis of Miscanthus

Abstract

Miscanthus is regarded as a desired bioenergy crop with enormous lignocellulose residues for biofuels and other chemical products. In this study, the effect of different pretreatments (including microwave, NaOH, CaO, and microwave + NaOH/CaO) on sugar yields was investigated, leading to largely varied hexose yields at 4.0–73.4% (% cellulose) released from enzymatic hydrolysis of pretreated Miscanthus residues. Among them, the highest yield of 73.4% for hexoses was obtained from 12% NaOH (w/v) solution pretreatment, whereas 1% CaO (w/w) and microwave pretreatment resulted in a lower hexose yield than the control (without pretreatment). The sugar yield from microwave followed with 1% NaOH pretreatment was 4.3 times higher than that of microwave followed with 1% CaO. However, the enzymatic hydrolysis efficiencies of the sample were 15.2% and 58.5% under microwave pretreatment followed by 12% NaOH or 12.5% CaO, respectively, which were lower than those of the same concentration of alkali (NaOH and CaO) pretreatments. To investigate the mechanism of varied enzymatic saccharification under different pretreatments, the changes in the surface structure and porosity of the Miscanthus‐pretreated lignocelluses were studied by means of Fourier transform infrared, Congo red staining, and scanning electron microscopy analysis. The results show that the different pretreatments destroy the cell wall cladding structure and reduce the bonding force between cellulose, hemicellulose, and lignin to different degrees, therefore increasing the accessibility of cellulose and enhancing cellulose digestion.

Recent Advances in Miscanthus Macromolecule Conversion: A Brief Overview

“…Enzymatic hydrolysis can liberate monomeric sugars in a very wide range, depending on the pretreatment method. For instance, Dai et al [ 74 ] recently examined how pretreatment methods such as microwave, NaOH, CaO and microwave + NaOH/CaO influenced the sugar yield from miscanthus. The hexose yield showed a substantial range from 4.0 to 73.4% (% on a cellulose basis).…”

MsaH2A.W is identified response to salt tolerance in Miscanthus sacchariflorus

“…These genome data are helpful for genetic improvement and functional genomic research of Miscanthus. To date, most research on Miscanthus has mainly focused on the utilization of biomass, cellulose/hemicellulose and forage (Bukowski et al, 2020;Dai et al, 2022;Golfier et al, 2017;Lee & Kuan, 2015;Xu et al, 2020). In addition, Miscanthus, as a perennial wild grass, has strong adaptability and potential to grow in marginal land such as saline land to avoid competing for arable lands with grain crops (Fu et al, 2009;Wang, Shao, et al, 2011).…”