Search

Saccharification of cellulose into glucose is a key step for the utilization of lignocellulose. Molten salt hydrate (MSH) is unique in selective hydrolysis of cellulose into glucose but the separation of formed glucose from MSH is challenging due to the high solubility of glucose in MSH. To address this issue, this work developed a method where a small dosage of MSH was applied to impregnate cellulose and convert it into water-soluble sugar with the degree of polymerization (DP) lower than 6, which can be readily hydrolyzed into glucose under mild conditions without sacrificing selectivity. Under the optimized impregnation condition at 110 °C for 2 h, cellulose was selectively converted into water-soluble sugar with a yield of 87.5%. Then the MSH can be efficiently dissolved and removed by anti-solvent isolation with n-butanol, resulting in a sugar recovery of 84.3%. We showed that the separation efficiency was influenced by anti-solvent polarity and oligosaccharides chain-length. Moreover, the production and separation of water-soluble sugar from corn stover was also investigated. 88.9% yield of water-soluble sugar was obtained from the impregnation of corn stover under the optimized reaction conditions. With the addition of n-butanol as an anti-solvent, the water-soluble sugar can be recovered from MSH with a selectivity of 86.7%. [ABSTRACT FROM AUTHOR]

Molten salt hydrates (MSHs) are remarkable in breaking through the recalcitrant structure of microcrystalline cellulose and raw biomass. After being pretreated in 60 wt% LiBr at 130 °C for 2 h, cellulose crystallinity as well as degree of polymerization (DP) decreased. It was found that 91.3% yield of pretreated cellulose was removed from MSHs by filteration followed by being hydrolyzed into glucose with a high yield of 75.3% by dilute acid under mild reaction conditions. The pretreatment process also works on raw corn stover hydrolysis. After being pretreated at 100 °C for 5 h, 88.4% yield of cellulose in biomass was recovered and can be hydrolyzed into 54.9% yield of glucose with dilute acid. It was found that the cellulose in corn stover can be easier degraded compared with microcrystalline cellulose during MSHs pretreatment, which dues to the formation of acetic acid from hemicellulose hydrolysis. The proposed pretreatment technique presents a promising potential for glucose production from biomass in a commercial way. Unlabelled Image • MSHs pretreatment effectively decreased cellulose crystallinity and DP. • After being pretreated at 130°C for 2 h, 91.3% of cellulose was removed from MSHs via filtration. • Enhanced glucose yield of 75.3% was obtained from pretreated cellulose hydrolysis at mild condition. • 88.4% cellulose recovery and 54.9% glucose yield were obtained from MSHs pretreatment and hydrolysis, respectively. [ABSTRACT FROM AUTHOR]