Effects of Green Liquor (GL) and Sodium Carbonate (SC) Pretreatment on Structural Characteristics of Wheat Stem Lignin

Cao, Tingyue; Jiang, Bo; Gu, Feng; Wu, Wenjuan; Jin, Yongcan

doi:10.1080/02773813.2017.1388821

Cited by 8 publications

(4 citation statements)

References 35 publications

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“…Cγ ester is another LCC linkage that exists between hemicellulosic uronic acid substituents and lignin’s side chain Cγ. The signals of CH 2 -γ in γ-esters were observed in the area of δ C / δ H 65–62/4.5–4.0, which can be overlapped by the signals of γ-acylated β- O -4 aryl ethers [22, 46]. The strong presence of LCC linkages in S-L and XOS spectra again demonstrated our previous speculation that the lignin fragments in XOS solid and the XOS fragment in solubilized lignin exist in the form of LCC structures.…”

Section: Resultsmentioning

confidence: 99%

A sustainable process for procuring biologically active fractions of high-purity xylooligosaccharides and water-soluble lignin from Moso bamboo prehydrolyzate

Huang

Wang

Liang³

et al. 2019

Biotechnol Biofuels

187

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Background Prehydrolyzate, which is from the prehydrolysis process in dissolving pulps industry, contains various sugar-derived and lignin compounds such as xylooligosaccharides (XOS), gluco-oligosaccharides, xylose, glucose, and soluble lignin (S-L). The XOS has several beneficial effects on human physiology. XOS and S-L in prehydrolyzate are difficult to efficiently fractionate due to their similar molecular weights and water solubility. In this work, we proposed a sustainable and green process using polystyrene divinylbenzene (PS-DVB) resin to simultaneously separate and recover XOS and S-L. Enzymatic hydrolysis with endo-1,4-β-xylanase and fermentation with P. stipites were sequentially applied to purify XOS to minimize xylose content as well as amplify contents of xylobiose and xylotriose. In addition, 2D-HSQC NMR was used to analyze the structural characteristics of XOS and S-L. Furthermore, the biological abilities of antioxidants and prebiotics of these fractions were investigated by scavenging radicals and cultivating intestinally beneficial bacterias, respectively. Results Results showed that PS-DVB resin could simultaneously separate XOS and solubilized lignin with excellent yields of 93.2% and 85.3%, respectively. The obtained XOS after being purified by enzymatic hydrolysis and fermentation contained 57.7% of xylobiose and xylotriose. 10.4% amount of inherent xylan was found in the S-L fraction obtained by PS-DVB resin separation. 2D-HSQC NMR revealed that lignin carbohydrate complexes existed in both XOS and S-L as covalent linkages between lignin and 4- O -methylglucuronoarabinoxylan. The biological application results showed that the antioxidant capacity of S-L was stronger than XOS, while XOS was superior in promoting growth of intestinal Bifidobacteria adolescentis and stimulating production of short-chain fatty acids by Lactobacillus acidophilus. Conclusions The proposed strategy of sequentially combining hydrophobic resin separation, enzymatic hydrolysis, and fermentation was successfully demonstrated and resulted in simultaneous production of high-quality XOS and solubilized lignin. These biomass-derived products in prehydrolyzate can be regarded as value-adding prebiotics and antioxidants. Electronic supplementary material The online version of this article (10.1186/s13068-019-1527-3) contains supplementary material, which is available to authorized users.

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Section: Resultsmentioning

confidence: 99%

A sustainable process for procuring biologically active fractions of high-purity xylooligosaccharides and water-soluble lignin from Moso bamboo prehydrolyzate

Huang

Wang

Liang³

et al. 2019

Biotechnol Biofuels

187

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“…Gu et al indicated that HS – exerts a synergistic effect with CO 3 2– to disrupt the more nonphenolic β-O-4 type in a GL solution than in other alkaline solutions . Consequently, GL pretreatment has better delignification selectivity as compared to SC pretreatment. , The resultant lignin obtained from GL pretreatment, however, faces the risk of sulfur contamination, which can complicate downstream conversion …”

Section: Impacts Of Alkali-based Pretreatment On Lignin Streammentioning

confidence: 99%

“…119 Consequently, GL pretreatment has better delignification selectivity as compared to SC pretreatment. 118,120 The resultant lignin obtained from GL pretreatment, however, faces the risk of sulfur contamination, which can complicate downstream conversion. 28…”

Section: Impacts Of Alkali-based Pretreatment Onmentioning

confidence: 99%

Alkali-Based Pretreatment-Facilitated Lignin Valorization: A Review

Zhang

Zhong

et al. 2020

Ind. Eng. Chem. Res.

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In an integrated biomass conversion process, pretreatment becomes an indispensable unit operation to enhance the accessibilities of cellulose and hemicelluloses for producing biofuels or chemicals. Besides carbohydrates utilization, lignin valorization is also considered as a key of achieving economic viability of biorefineries. The pretreatments using alkaline reagents exhibit a superior performance on boosting the yield of fermentable sugars by separating the lignin fraction and altering lignin structures and properties, offering the potential to facilitate the covalorization of lignin and carbohydrates. The diverse lignin recovered from alkali-based pretreatment affects the subsequent lignin depolymerization and conversion process due to the varying chemical and physical properties. In this review, the features and performances of different types of alkali-based pretreatments in the modifications to lignin are discussed. Also, the drill-down analysis of the promising methods to depolymerize lignin provides deep insights toward the conversion and upgrading of lignin isolated from alkaline pretreatment.

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“…Challenging this implementation is the complexity of lignocellulosic cell walls, which, existing as a complex matrix of cross-linked biopolymers (cellulose, hemicellulose, and lignin), is difficult to disrupt [5, 6]. This organized and compact structure exists around the cellulose, which can only be bio-converted into its constituent glucose if sufficient structural disruption around cellulose’s surrounding biopolymers takes place [7]. Disrupting the complex structure of lignocellulosic materials by pretreatment is a necessary step for the biorefinery process.…”

Section: Introductionmentioning

confidence: 99%

Enhancing enzymatic digestibility of waste wheat straw by presoaking to reduce the ash-influencing effect on autohydrolysis

Tang

Huang

et al. 2019

Biotechnol Biofuels

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Background The acid buffering capacity of high free ash in waste wheat straw (WWS) has been revealed to be a significant hindrance on the efficiency of autohydrolysis pretreatment. Previous researches have mainly relied on washing to eliminate the influence of ash, and the underlying mechanism of the ash influencing was not extensively investigated. Presently, studies have found that cations can destroy the acid buffering capacity of ash through cation exchange. Herein, different cations were applied to presoak WWS with the aim to overcome the negative effects of ash on autohydrolysis efficiency, further improving its enzymatic digestibility. Results Results showed that cations can be adsorbed on the surface of the material by electrostatic adsorption to change the acid buffering capacity of WWS. The acid buffering capacity of 120 mM Fe2+ presoaked WWS is reduced from 226.3 mmol/pH-kg of original WWS to 79.3 mmol/pH-kg. This reduced the autohydrolysis pretreatment medium pH from 5.7 to 3.8 and promoted the removal of xylan from 61.7 to 83.7%. In addition, the enzymatic digestibility of WWS was enhanced from 49.7 to 86.3% by presoaking with 120 mM Fe2+ solution. The relationship between enzymatic accessibility and hydrophobicity with enzymatic digestibility of the autohydrolyzed WWS was analyzed. Conclusions The results showed that the acid buffering capacity of the high free ash was detrimental for the autohydrolysis efficiency of WWS. After WWS was presoaked with different cations, the acid buffering capacity of ash was weakened by cation exchange and electrostatic adsorption, which improved the autohydrolysis efficiency. The results expound that the enzymatic digestibility of WWS can be enhanced through presoaking to reduce the ash-influencing effect on autohydrolysis.

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Effects of Green Liquor (GL) and Sodium Carbonate (SC) Pretreatment on Structural Characteristics of Wheat Stem Lignin

Cited by 8 publications

References 35 publications

A sustainable process for procuring biologically active fractions of high-purity xylooligosaccharides and water-soluble lignin from Moso bamboo prehydrolyzate

A sustainable process for procuring biologically active fractions of high-purity xylooligosaccharides and water-soluble lignin from Moso bamboo prehydrolyzate

Alkali-Based Pretreatment-Facilitated Lignin Valorization: A Review

Enhancing enzymatic digestibility of waste wheat straw by presoaking to reduce the ash-influencing effect on autohydrolysis

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