Pseudo-lignin retarded bioconversion of sugarcane bagasse holocellulose after liquid hot water and acid pretreatments

Pseudo-lignin derived from the condensation of carbohydrate degradation products can retard the bioconversion of lignocellulose. In this work, liquid hot water (150 to 190 °C) and 1% H2SO4 pretreatments (130 to 190 °C) were used on sugarcane bagasse holocellulose for 3 h to generate pseudo-lignin. The effects of pseudo-lignin generation on structural characteristics and bioconversion of substrates were evaluated. The results showed that the formation of pseudo-lignin increased the hydrophobicity of the substrates. After LHW pretreatments and acid pretreatments at low temperatures (<150 °C), most of the xylans were removed, yielding 2.1 to 5.4% pseudo-lignin. Increasing acid pretreatment temperature to 170 and 190 °C yielded 34.3% and 93.6% pseudo-lignin, respectively. After pretreatment, the accessibilities and bioconversions of substrates were enhanced by degradation of xylans, increasing glucose conversions and bioethanol productions of substrates from 53.2 to 85.3%, and 9.9 to 13.1 g/L, respectively. However, large amounts of pseudo-lignin were generated during acid pretreatments at 170 °C, reducing glucose conversion and bioethanol yield to 45.6% and 6.3 g/L, respectively.

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Impact of Liquid Hot Water Pretreatment on the Structural Changes of Sugarcane Bagasse Biomass for Sugar Production

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.472.774 ◽

2014 ◽

Vol 472 ◽

pp. 774-779 ◽

Cited By ~ 2

Author(s):

Hong Dan Zhang ◽

Shu Bin Wu

Keyword(s):

Sugarcane Bagasse ◽

Structural Changes ◽

Lignin Content ◽

Hot Water ◽

Raw Material ◽

Liquid Hot Water Pretreatment ◽

Liquid Hot Water ◽

Water Pretreatment ◽

Pretreatment Temperature ◽

Hot Water Pretreatment

Liquid hot water pretreatment, as an initial step in an alternative use of lignocellulosic biomass to produce fermentable sugar, was performed in this study. The effect of pretreatment temperature range from 160 to 200 °C on the hemicellulose degradation (the yields of glucose and xylose, as well as inhibitors) and cellulose enzymatic digestibility were evaluated. The results indicated that the maximum xylose yields (combined 2.23 g xylose and 13.20 g xylo-oligosaccharides per 100g raw material) in prehydrolysate liquid were obtained at 180 °C. The untreated and pretreated solid residues were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and fourier transform infrared spectroscopy (FT-IR). The results showed that liquid hot water pretreatment removed a large number of hemicellulose and resulted in enriched cellulose and lignin content in the pretreated residues. Due to the effective removal of hemicellulose, the maximum glucose yield in enzyme hydrolyzate reached 37.27 g per 100 g raw material (after the pretreatment temperature of 200°C), representing 90.13% of glucose in the sugarcane bagasse.

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Xylo-oligosaccharides and Ethanol Production from Liquid Hot Water Hydrolysate of Sugarcane Bagasse

BioResources ◽

10.15376/biores.10.1.30-40 ◽

2014 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

Qiang Yu ◽

Chunxun Xu ◽

Xinshu Zhuang ◽

Zhenhong Yuan ◽

Minchao He ◽

...

Keyword(s):

Ethanol Production ◽

Sugarcane Bagasse ◽

Hot Water ◽

Liquid Hot Water

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Effect of Lignin Content on Cellulolytic Saccharification of Liquid Hot Water Pretreated Sugarcane Bagasse

Molecules ◽

10.3390/molecules25030623 ◽

2020 ◽

Vol 25 (3) ◽

pp. 623 ◽

Cited By ~ 7

Author(s):

Rafaela I. S. Ladeira Ázar ◽

Sidnei Emilio Bordignon-Junior ◽

Craig Laufer ◽

Jordan Specht ◽

Drew Ferrier ◽

...

Keyword(s):

Sugarcane Bagasse ◽

Plant Cell Wall ◽

Lignin Content ◽

Blocking Agent ◽

Enzymatic Digestion ◽

Hot Water ◽

Severity Factor ◽

Liquid Hot Water ◽

Cellulose Digestibility ◽

Pretreated Sugarcane Bagasse

Lignin contributes to the rigid structure of the plant cell wall and is partially responsible for the recalcitrance of lignocellulosic materials to enzymatic digestion. Overcoming this recalcitrance is one the most critical issues in a sugar-flat form process. This study addresses the effect of low lignin sugarcane bagasse on enzymatic hydrolysis after liquid hot water pretreatment at 190 °C and 20 min (severity factor: 3.95). The hydrolysis of bagasse from a sugarcane line selected for a relatively low lignin content, gave an 89.7% yield of cellulose conversion to glucose at 40 FPU/g glucan versus a 68.3% yield from a comparably treated bagasse from the high lignin bred line. A lower enzyme loading of 5 FPU/g glucan (equivalent to 3.2 FPU/g total solids) resulted in 31.4% and 21.9% conversion yields, respectively, for low and high lignin samples, suggesting the significance of lignin content in the saccharification process. Further increases in the enzymatic conversion of cellulose to glucose were achieved when the bagasse sample was pre-incubated with a lignin blocking agent, e.g., bovine serum albumin (50 mg BSA/g glucan) at 50 °C for 1 h prior to an actual saccharification. In this work, we have demonstrated that even relatively small differences in lignin content can result in considerably increased sugar production, which supports the dissimilarity of bagasse lignin content and its effects on cellulose digestibility. The increased glucose yields with the addition of BSA helped to decrease the inhibition of non-productive absorption of cellulose enzymes onto lignin and solid residual lignin fractions.

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Ethanol–water organosolv delignification of liquid hot water (LHW) pretreated sugarcane bagasse enhanced by high–pressure carbon dioxide (HP–CO2)

Industrial Crops and Products ◽

10.1016/j.indcrop.2016.10.003 ◽

2016 ◽

Vol 94 ◽

pp. 942-950 ◽

Cited By ~ 11

Author(s):

Leandro Vinícius Alves Gurgel ◽

Maria Teresa Borges Pimenta ◽

Antonio Aprigio da Silva Curvelo

Keyword(s):

Carbon Dioxide ◽

High Pressure ◽

Sugarcane Bagasse ◽

Hot Water ◽

Liquid Hot Water ◽

Pretreated Sugarcane Bagasse

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Integral Analysis of Liquid-Hot-Water Pretreatment of Wheat Straw: Evaluation of the Production of Sugars, Degradation Products, and Lignin

Sustainability ◽

10.3390/su14010362 ◽

2021 ◽

Vol 14 (1) ◽

pp. 362

Author(s):

Sebastian Serna-Loaiza ◽

Manuel Dias ◽

Laura Daza-Serna ◽

Carla C. C. R. de Carvalho ◽

Anton Friedl

Keyword(s):

Acetic Acid ◽

Wheat Straw ◽

Solid Phase ◽

Degradation Products ◽

Hot Water ◽

Liquid Hot Water ◽

Water Pretreatment ◽

Renewable Feedstock ◽

Hot Water Pretreatment ◽

Potential Use

Developing sustainable biorefineries is an urgent matter to support the transition to a sustainable society. Lignocellulosic biomass (LCB) is a crucial renewable feedstock for this purpose, and its complete valorization is essential for the sustainability of biorefineries. However, it is improbable that a single pretreatment will extract both sugars and lignin from LCB. Therefore, a combination of pretreatments must be applied. Liquid-hot-water (LHW) is highlighted as a pretreatment for hemicellulose hydrolysis, conventionally analyzed only in terms of sugars and degradation products. However, lignin is also hydrolyzed in the process. The objective of this work was to evaluate LHW at different conditions for sugars, degradation products, and lignin. We performed LHW at 160, 180, and 200 °C for 30, 60, and 90 min using wheat straw and characterized the extract for sugars, degradation products (furfural, hydroxymethylfurfural, and acetic acid), and lignin. Three conditions allowed reaching similar total sugar concentrations (~12 g/L): 160 °C for 90 min, 180 °C for 30 min, and 180 °C for 60 min. Among these, LHW performed at 160 °C for 90 min allowed the lowest concentration of degradation products (0.2, 0.01, and 1.4 g/L for furfural, hydroxymethylfurfural, and acetic acid, respectively) and lignin hydrolysis (2.2 g/L). These values indicate the potential use of the obtained sugars as a fermentation substrate while leaving the lignin in the solid phase for a following stage focused on its extraction and valorization.

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