Mild Acid-Catalyzed Atmospheric Glycerol Organosolv Pretreatment Effectively Improves Enzymatic Hydrolyzability of Lignocellulosic Biomass

Pascal, Kaneza; Ren, Hongyan; Sun, Fubao; Guo, Shuxian; Hu, Jinguang; He, Jing

doi:10.1021/acsomega.9b02993

Cited by 31 publications

(15 citation statements)

References 33 publications

(73 reference statements)

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“…5−9 Among them, glycerol pretreatment is attractive because glycerol is a low-cost, nontoxic, nonflammable solvent, which is widely available as a by-product of the biodiesel industry. 10,11 In addition, any residual glycerol remaining in the biomass after pretreatment is less inhibitory to enzymatic hydrolysis and fermentation compared with other solvents. In addition, many microorganisms can use glycerol as a carbon source for biofuel and biochemical production.…”

Section: ■ Introductionmentioning

confidence: 99%

Acid-Catalyzed Glycerol Pretreatment of Sugarcane Bagasse: Understanding the Properties of Lignin and Its Effects on Enzymatic Hydrolysis

Hassanpour

Abbasabadi

Gebbie

et al. 2020

ACS Sustainable Chem. Eng.

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In this study, lignin from acid-catalyzed glycerol (AG) pretreatment of sugarcane bagasse was recovered and characterized. Its effects on enzymatic hydrolysis and cellulase recycling were then investigated. Prior to lignin recovery, a two-step dilute acid and AG pretreatment was used to deconstruct sugarcane bagasse, which led to a glucan enzymatic digestibility of 99%, a glucose yield of 91%, and a xylose yield of 67%. Following enzymatic hydrolysis, lignin-rich residues were recovered by simple filtration at a lignin yield of 63% and a lignin purity of 90%. Two-dimensional heteronuclear single quantum correlation nuclear magnetic resonance analysis showed that glycerol had modified the bagasse lignin through α-etherification of β-aryl ethers and γ-esterification of hydroxycinnamic acids, generating a novel lignin structure. 31P NMR analysis showed that the recovered lignin had a high number of aliphatic hydroxyl groups suggesting that it is highly hydrophilic in nature. As a result, the AG lignin did not inhibit enzymatic hydrolysis of pretreated bagasse, and cellulases adsorbed onto lignin-rich solid residues were successfully recycled three times, leading to an average glucan digestibility of 93% (for a total of four batches) at an average cellulase dosage of only 4.1 FPU/g glucan. This study provides new and important information on AG pretreatment, which is critical toward the development of biorefinery processes based on this pretreatment.

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Section: ■ Introductionmentioning

confidence: 99%

Acid-Catalyzed Glycerol Pretreatment of Sugarcane Bagasse: Understanding the Properties of Lignin and Its Effects on Enzymatic Hydrolysis

Hassanpour

Abbasabadi

Gebbie

et al. 2020

ACS Sustainable Chem. Eng.

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“…Commercial Cellic CTec2 (141 FPU g –1 ) was a generous gift from Novozymes. Sugarcane bagasse was subjected to the optimized atmospheric glycerol organosolv (AGO) pretreatment. , Briefly, 100 g of dry sugarcane bagasse was mixed with 1000 g of 95% glycerol and 0.2% (w/w) NaOH (0.1% (v/w) H 2 SO 4 ) as the catalyst at the start of the al-AGO (ac-AGO) pretreatment process. The al-AGO pretreatment was conducted at 240 °C for 30 min in a three-necked round-bottom flask (5 L), while ac-AGO pretreatment was conducted at 200 °C for 10 min.…”

Section: Methodsmentioning

confidence: 99%

“…6 Further, acidcatalyzed AGO (ac-AGO) pretreatment optimized at 200 °C for 15 min with a 0.06% H 2 SO 4 addition tended to result in hemicellulose removal (82%) with an extremely high rate of cellulose retention (98%). 7 On the other hand, alkali-catalyzed AGO (al-AGO) pretreatment (240 °C, 30 min, 0.2% NaOH) was apt to result in delignification (70%). 8 Thus, these AGO pretreatment processes have displayed a notable selectivity for deconstructing lignocellulosic biomass by removing more lignin and/or hemicellulose but with good cellulose retention.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Even milder AGO pretreatment conditions (220 °C, 2 h) could remove ∼70% of the lignin with 94% of the cellulose left over . Further, acid-catalyzed AGO (ac-AGO) pretreatment optimized at 200 °C for 15 min with a 0.06% H 2 SO 4 addition tended to result in hemicellulose removal (82%) with an extremely high rate of cellulose retention (98%) . On the other hand, alkali-catalyzed AGO (al-AGO) pretreatment (240 °C, 30 min, 0.2% NaOH) was apt to result in delignification (70%) …”

Section: Introductionmentioning

confidence: 99%

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Synergism of Recombinant Podospora anserina PaAA9B with Cellulases Containing AA9s Can Boost the Enzymatic Hydrolysis of Cellulosic Substrates

Long

Yang

Ren

et al. 2020

ACS Sustainable Chem. Eng.

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To achieve a fast and efficient cellulose hydrolysis with low enzyme loading remains a challenge for an economically feasible biomass biorefinery process. The synergism between cellulase and lytic polysaccharide monooxygenases (LPMOs) has demonstrated great promise, but it appears that such synergistic effects are highly substrate-dependent. In addition, the need for an efficient method of LPMO production has also limited its application. In this study, the production of Podospora anserina AA9B (PaAA9B), one of the most active LPMOs, was optimized by using double-plasmid coexpression in Pichia pastoris, and its hydrolysis-boosting effects on cellulases were assessed on model cellulosic materials and on our in-house-optimized atmospheric glycerol organosolv (AGO)-pretreated lignocellulosic substrates. The results showed that the double-plasmid coexpression technique successfully improved the PaAA9B production, where up to three times more PaAA9B (3.34 g L −1 ) was expressed in the 5 L bioreactor after 4 days of induction. The addition of recombinant PaAA9B to Cellic CTec2 (CTec2) significantly boosted the cellulose hydrolysis of a filter paper and Avicel by 2.3-and 1.4-folds, respectively, while no effects were observed on carboxymethyl cellulose (CMC). When lignocellulosic substrates were assessed, the PaAA9B also successfully enhanced the cellulose hydrolysis of both acid-catalyzed (ac) and alkali-catalyzed (al) AGO-pretreated sugarcane bagasses by 30 and 20%, respectively, at a 5% solid loading (w/v). At industrially relevant high-solid loading (20% w/v) hydrolysis of an al-AGO-pretreated substrate, the combination of 1.0 mg of PaAA9B and 3 FPU of cellulase per gram of substrate achieved 83% cellulose hydrolysis with 105 g L −1 of the corresponding glucose concentration after 72 h. These results indicated that the double-plasmid coexpression strategy is viable for the high-yield PaAA9B production. The mixture of PaAA9B and cellulase enzymes containing other AA9s exhibited a strong cosynergistic interaction and further boosted the enzymatic hydrolysis of both model cellulosic substrates and our optimized AGO-pretreated lignocellulosic biomass with industrially relevant enzyme loading. This study sheds light on the industrially relevant PaAA9B utilization in the enzymatic hydrolysis of lignocellulosic substrates.

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“…Corn stover is composed of 37% cellulose and 19.8% xylan [12]. Various pretreatment methods have been reported, such as alkaline [8,13,14], acid [3,15,16], acid and alkaline [17], ethanol [18], glycerol [19], hydrogen peroxide [20,21], alkaline hydrogen peroxide [22,23], ionic liquids [24,25] and deep eutectic solvents [26,27].…”

Section: Introductionmentioning

confidence: 99%

Coproduction of xylose and biobutanol from corn stover via recycling of sulfuric acid pretreatment solution

Dong

Liu

et al. 2020

Syst Microbiol and Biomanuf

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Sulfuric acid was used in the pretreatment of corn stover to obtain xylose as a value-added by-product, and the pretreated corn stover (Pre-CS) was hydrolyzed to produce glucose for butanol fermentation. The aim of this work is to achieve high xylose accumulation and reduced wastewater by recycling the pretreatment solution. The pretreatment conditions were optimized as follows: 180 °C, 15 min, 1:7 solid-liquid ratio (w/w), 0.6% H 2 SO 4 (w/w, first batch)/0.9% H 2 SO 4 (w/w, second and third batches), in which pretreatment solution was recycled for three times. Under above conditions, pretreatment solution containing 56.3 g/L xylose and 4.5 g/L glucose was obtained. Pre-CS residue was further hydrolyzed by cellulase to achieve 35.7-39.9 g/L glucose. The condensed corn stover hydrolysate was subjected to simultaneous detoxification and sterilization using 1% (w/w) activated carbon and then applied in butanol fermentation. The highest butanol titer of 9.5 g/L was obtained in 72 h. The results provide a practical approach for coproducing xylose and biobutanol from corn stover.

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Mild Acid-Catalyzed Atmospheric Glycerol Organosolv Pretreatment Effectively Improves Enzymatic Hydrolyzability of Lignocellulosic Biomass

Cited by 31 publications

References 33 publications

Acid-Catalyzed Glycerol Pretreatment of Sugarcane Bagasse: Understanding the Properties of Lignin and Its Effects on Enzymatic Hydrolysis

Acid-Catalyzed Glycerol Pretreatment of Sugarcane Bagasse: Understanding the Properties of Lignin and Its Effects on Enzymatic Hydrolysis

Synergism of Recombinant Podospora anserina PaAA9B with Cellulases Containing AA9s Can Boost the Enzymatic Hydrolysis of Cellulosic Substrates

Coproduction of xylose and biobutanol from corn stover via recycling of sulfuric acid pretreatment solution

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