Effect of Acidic Guanidine Hydrochloride DES Pretreatment on Enzymatic Hydrolysis of Corn Stalk
To improve the pretreatment efficiency of biomass with guanidine hydrochloride/ethylene glycol deep eutectic solvents(DES),the research was carried out on the pretreatment of corn stalk using DES systems with guanidine hydrochloride(GH)as the hydrogen bond acceptor,and ethylene glycol(EG)and 6 organic acids as hydrogen bond donors.The variations in the composition of the stalk before and after pretreatment and the sugar yield after enzymatic hydrolysis were investigated,and the mechanism by which GH,EG,and citric acid(CA)DES(GH/EG/CA)facilitated the enzymatic hydrolysis of corn stalk was explored.The research results showed that all organic acids had the role of promoting the removal of xylan and lignin.The GH/EG/CA system exhibited the best pretreatment effect,with the reducing sugar yield of 86.36％after 72 h of enzymatic hydrolysis of the pretreated corn stalk,which were 3.3 and 1.8 times that of the untreated and DES-pretreated stalk without acid addition(GH/EG),respectively.The recovery rate of glucan after pretreatment was 94.21％,and the removal rates of xylan and lignin were 65.14％and 42.23％,respectively.The morphology and structure of the stalk before and after pretreatment were analyzed using scanning electron microscopy,X-ray diffraction,physical adsorption,infrared spectroscopy,thermogravimetry,and a contact angle meter,etc.The surface roughness,crystallinity(ICr),and specific surface area of the untreated,GH/EG and GH/EG/CA pretreated corn stalk increased gradually,which was attributed to the increase in cellulose content and the dissolution of hemicellulose and lignin components after pretreatment.After pretreatment,the characteristic functional groups of cellulose on the surface of straw were more abundant,the thermal stability was better,and the water penetration was faster,so as to realize the efficient separation and transformation of corn straw and greatly improve the enzymatic hydrolysis efficiency of lignocellulose.The resulting glucose can be further fermented to produce bio-based ethanol,and lignin can be further used as a raw material for bio-based materials.
万方数据
维普
