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To understand the effects of the biomass constituents for enzymatic hydrolysis, a tropical hardwood, Eucalyptus pellita , was employed to change the content of chemical constituents and regression assessment was progressed. The liquid hot water and acid-chlorite pretreatment controlled hemicellulose and lignin removal rate from 3.1 to 91.7% and from 4.4 to 99.1%, respectively. Total lignin in E. pellita (34.8%) was obviously reduced up to 9.0% under 4 g of sodium chlorite and 0.8 mL of acetic acid with 3 times loading. In this case, acid-insoluble lignin (2.4%) was entirely eliminated compared with that of E. pellita (29.0%), whereas acid-soluble lignin (6.6%) was preferably increased compared with of E. pellita (2.3%). The maximum glucose yield (87.5%) after the combined pretreatment and enzymatic hydrolysis were dramatically improved compared with that of liquid hot water pretreatment alone (28.2%). Meanwhile, a high glucose yield (83.9%) could also be obtained by acid-chlorite pretreatment alone. The adjusted R-squared value of hemicellulose and lignin removal rate (0.9285) and lignin removal rate alone (0.9063) with glucose yield was determined by linear regression analysis. • Relationship between chemical constituents and glucose yield was evaluated. • 99.1% of lignin was selectively removed by acid-chlorite pretreatment. • High glucose yield over 85% was achieved after combined pretreatment. • Only hemicellulose removal had no significant effect on glucose production. • Hemicellulose and lignin had synergetic effect on glucose yield (R2 = 0.9285). [ABSTRACT FROM AUTHOR]

The main purpose of this study was to produce succinic acid from hemicellulose in lignocellulosic biomass by successive process without purification as a biorefinery concept. Liquid hot water (LHW) treatment was conducted to extract water soluble hemicelluloses from Quercus mongolica to produce furfural from lignocellulosic biomass. Additional acid catalyzed dehydration was conducted to liquid hydrolysate from LHW treatment for furfural production. At 170 °C of reaction temperature, 42% of furfural yield was achieved from pentose in liquid hydrolysate. This Acid treated liquor (ATL) was treated with hydrogen peroxide to oxidize furfural to C4 dicarboxylic acid such as succinic or maleic acid. Main product was succinic acid which is produced by oxidation of furfural, and minor amount of maleic acid was produced via oxidation. The xylose was degraded to furfural and then oxidized to succinic acid, while acid soluble lignin inhibited succinic acid production by reacting with intermediates of succinic acid. This results indicated that hemicellulose rich liquid hydrolysate has potential to source for succinic acid without further purification. • Liquid hot water treatment was conducted to extract hemicellulose from biomass. • Furfural was produced via acid catalyzed dehydration of hemicellulose. • Sequential addition of hydrogen peroxide oxidized furfural to succinic acid. • Xylose in liquid was oxidized to succinic acid. • Acid soluble lignin tended to react with intermediates of succinic acid. [ABSTRACT FROM AUTHOR]

Eucalyptus pellita is known as attractive biomass, and it has been utilized for eucalyptus oil, furniture, and pulp and paper production that causes a significant amount of byproducts. Liquid hot water treatment depending on combined severity factor (CSF) was subjected to isolate hemicellulose fraction from E. pellita and to produce xylooligosaccharides (XOS). The xylan extraction ratio based on the initial xylan content of the feedstock was maximized up to 77.6% at 170 °C for 50 min condition (CSF: 1.0), which had accounted for XOS purity of 76.5% based on the total sugar content of the liquid hydrolysate. In this condition, the sum of xylobiose, xylotriose, and xylotetraose which has a low degree of polymerization (DP) of 2 to 4 was determined as 80.6% of the total XOS. The highest XOS production score established using parameters including the xylan extraction ratio, XOS purity, and low DP XOS ratio was 5.7 at CSF 1.0 condition. XOS production score evaluated using the CSF is expected to be used as a productivity indicator of XOS in the industry (R-squared value: 0.92). [ABSTRACT FROM AUTHOR]

• A sequential process was proposed for total utilization of woody biomass. • Hemicellulose was selectively decomposed with producing xylooligomers. • Lignin was degraded by 50% diluted PAA treatment with producing dicarboxylic acids. • Cellulose accessibility to the enzyme was improved by constituent deconstruction. For improving the economic efficiency of the biorefining concept, selective decomposition and separation of biomass components is indispensable. In this respect, a sequential pretreatment process consisting of liquid hot water treatment and diluted peracetic acid (PAA) treatment was proposed for total utilization of lignocellulosic woody biomass. During the liquid hot water treatment, hemicellulose can be decomposed efficiently without significant loss of cellulose and lignin, implying the possibility for xylooligomer production by thermochemical treatment. In the PAA treatment, lignin was successfully degraded and liquefied using a 50% diluted PAA solvent, suggesting the possibility of dicarboxylic acid production. After the sequential process proposed in this study, the cellulose accessibility to the enzyme could be maximized by inducing selective deconstruction of hemicellulose and lignin. [ABSTRACT FROM AUTHOR]