Current perspective on pretreatment technologies using lignocellulosic biomass: An emerging biorefinery concept

Kumar, Brijesh; Bhardwaj, Nishi Kant; Agrawal, Komal; Chaturvedi, Venkatesh; Verma, Pradeep

doi:10.1016/j.fuproc.2019.106244

Cited by 502 publications

(190 citation statements)

References 273 publications

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“…For example, the complexity of the cell wall structure, degree of polymerization, cellulose crystallinity, extent of lignification and compositional heterogeneity even within one species of biomass, etc. [6,7] are such major factors. Therefore, pretreatment, to make biomass available for subsequent processing, has been envisaged as an unavoidable step in biomass refining processes [8].…”

Section: Introductionmentioning

confidence: 99%

Effects of Gamma-Valerolactone Assisted Fractionation of Ball-Milled Pine Wood on Lignin Extraction and Its Characterization as Well as Its Corresponding Cellulose Digestion

et al. 2020

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Gamma-valerolactone (GVL) was found to be an effective, sustainable alternative in the lignocellulose defragmentation for carbohydrate isolation and, more specifically, for lignin dissolution. In this study, it was adapted as a green pretreatment reagent for milled pinewood biomass. The pretreatment evaluation was performed for temperature (140–180 °C) and reaction time (2–4 h) using 80% aqueous GVL to obtain the highest enzymatic digestibility of 92% and highest lignin yield of 33%. Moreover, the results revealed a positive correlation (R2 = 0.82) between the lignin removal rate and the crystallinity index of the treated biomass. Moreover, under the aforementioned conditions, lignin with varying molecular weights (150–300) was obtained by derivatization followed by reductive cleavage (DFRC). 2D heteronuclear single quantum coherence nuclear magnetic resonance (2D-HSQC-NMR) spectrum analysis and gel permeation chromatography (GPC) also revealed versatile lignin properties with relatively high β-O-4 linkages (23.8%–31.1%) as well as average molecular weights of 2847–4164 with a corresponding polydispersity of 2.54–2.96, indicating this lignin to be a heterogeneous feedstock for value-added applications of biomass. All this suggested that this gamma-valerolactone based pretreatment method, which is distinctively advantageous in terms of its effectiveness and sustainability, can indeed be a competitive option for lignocellulosic biorefineries.

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Section: Introductionmentioning

confidence: 99%

Effects of Gamma-Valerolactone Assisted Fractionation of Ball-Milled Pine Wood on Lignin Extraction and Its Characterization as Well as Its Corresponding Cellulose Digestion

et al. 2020

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“…Furthermore, the amount of inhibitory by-products formed during the hydrolysis can be decreased by the choice of the pretreatment method [11,17]. Several pretreatment methods exist, including physical, chemical, physicochemical, biological, ultrasound, and microwave-assisted methods and combined methods [18][19][20][21][22]. Physical pretreatment, including mechanical operations, aims to decrease the size of the biomass particles and increase the surface area of the particles [18].…”

Section: Introductionmentioning

confidence: 99%

“…The pretreatment with several acids and alkalines as well as an organosolv process were studied [25]. Even though a chemical pretreatment is an efficient way to remove hemicelluloses and the sugar yield is higher than with a physical treatment, the formation of the inhibitory products and corrosion of the equipment have to be considered [19]. Joined physical and chemical pretreatment combines characters from each pretreatment process.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Mechanocatalytic Pretreatment on the Structure and Depolymerization of Willow

et al. 2020

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In this study, the effect of a mechanocatalytic pretreatment on the structure of willow and sugar release from pretreated willow was explored. In the mechanocatalytic approach, the pretreatment consists of solvent-free impregnation with sulfuric acid and a mechanical treatment with ball milling. Willow sawdust and pretreated samples were analyzed with field emission scanning electron microscope and X-ray diffraction. The products in the sugar solution were determined as the total reducing sugars with the 3,5-dinitrosalicylic acid method and monosaccharides with capillary electrophoresis. According to the results, milling increased the sugar production, depending on the sulfuric acid load. The milling parameters, such as the rotation speed of the mill, the catalyst-to-willow ratio, and the milling time influenced the amount of sugars in the hydrolysate and the composition of the sugar solution produced. Changes were observed in the surface of the willow particles as well as changes in the crystalline structure. Glucose and xylose yields increased after 15 min of milling and reached their maximum level after 45 min of milling with the 0.5 mmol/g sulfuric acid load.

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“…Fermentation serves as bioconversion to alcohols of sugar hydrolysates derived from polysaccharide-rich lignocellulose biomass. However, a major challenge linked to hydrolysis-fermentation of lignocellulose biomass is the recalcitrant nature of the material to enzymatic conversion [3,4]. Physicochemical pretreatment is thus required to disrupt the compact crystalline structure and allow enzymatic access to the polysaccharides within, to release fermentable sugars [3,5,6].…”

Section: Introductionmentioning

confidence: 99%

“…However, a major challenge linked to hydrolysis-fermentation of lignocellulose biomass is the recalcitrant nature of the material to enzymatic conversion [3,4]. Physicochemical pretreatment is thus required to disrupt the compact crystalline structure and allow enzymatic access to the polysaccharides within, to release fermentable sugars [3,5,6]. The majority of such pre-treatment methods result in signi cant quantities of degradation products being formed, which have inhibitory effects of subsequent biological conversions [5,[7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Rational Engineering of Saccharomyces Cerevisiae Towards Improved Tolerance to Multiple Inhibitors in Lignocellulose Fermentations

Brandt

García-Aparicio

Görgens

et al. 2020

Preprint

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Background: The fermentation of lignocellulose hydrolysates to ethanol require robust xylose capable Saccharomyces cerevisiae strains able to operate in the presence of microbial inhibitory stresses. This study aimed at developing industrial S. cerevisiae strains with enhanced tolerance towards pretreatment-derived microbial inhibitors, by identifying novel gene combinations that confer resistance to multiple inhibitors (thus cumulative inhibitor resistance phenotype) with minimum impact on the xylose fermentation ability. The strategy consisted of multiple sequential delta-integrations of double gene cassettes containing one gene conferring broad inhibitor tolerance (ARI1, PAD1 or TAL1) coupled with an inhibitor specific gene (ADH6, FDH1 or ICT1). The performances of the transformants were compared with the parental strain in terms of biomass growth, ethanol yields and productivity, as well as detoxification capacities in a synthetic inhibitor cocktail, sugarcane bagasse hydrolysate as well as hardwood spent sulphite liquor.Results: The first and second round of delta-integrated transformants exhibited a trade-off between biomass and ethanol yield. Transformants showed increased inhibitor resistance phenotypes relative to parental controls specifically in fermentations with concentrated spent sulphite liquors at 40% and 80% v/v concentrations in 2% SC media. Unexpectedly, the xylose fermentation capacity of the transformants was reduced compared to the parental control, but certain combinations of genes had a minor impact (e.g. TAL1 + FDH1). The TAL1+ ICT1 combination negatively impacted on both biomass growth and ethanol yield, which could be linked to the ICT1 protein increasing transformant susceptibility to weak acids and temperature due to cell membrane changes. Conclusions: The integration of the selected genes was proven to increase tolerance to pretreatment inhibitors in synthetic or industrial hydrolysates, but they were limited to the fermentation of glucose. However, some genes combination sequences had a reduced impact on xylose conversion.

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Current perspective on pretreatment technologies using lignocellulosic biomass: An emerging biorefinery concept

Cited by 502 publications

References 273 publications

Effects of Gamma-Valerolactone Assisted Fractionation of Ball-Milled Pine Wood on Lignin Extraction and Its Characterization as Well as Its Corresponding Cellulose Digestion

Effects of Gamma-Valerolactone Assisted Fractionation of Ball-Milled Pine Wood on Lignin Extraction and Its Characterization as Well as Its Corresponding Cellulose Digestion

The Effect of Mechanocatalytic Pretreatment on the Structure and Depolymerization of Willow

Rational Engineering of Saccharomyces Cerevisiae Towards Improved Tolerance to Multiple Inhibitors in Lignocellulose Fermentations

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