The effect of isolation method on the chemical structure of residual lignin

Jääskeläinen, Anna Stiina; Sun, Yuxuan; Argyropoulos, Dimitris S.; Tamminen, Tarja; Hortling, Bo

doi:10.1007/s00226-003-0163-y

Cited by 111 publications

(47 citation statements)

References 9 publications

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“…It is known that cellulases do not affect the lignin structure [48], while it can be significantly modified by steam treatments [19,49]. Li et al have previously characterised steam explosion lignins and found that the ␤-O-4 linkages disappeared and that there was a slight increase in the amount of carboxyl groups in alkali extracted steam-pretreatment lignins [49] (same pretreatment parameters and equipment as we used on our substrate).…”

Section: Lignin Structurementioning

confidence: 86%

“…Because SPS carbohydrate hydrolysis was found to be efficient in the presence of PEG 4000, the hydrolysis residue was assessed by 31 P NMR and compared to milled wood lignin isolated from spruce. The lignin isolation method was previously found to be crucial step in lignin analytics [48]. 31 P NMR is an effective tool for lignin analysis and allows quantitative detection of the different classes of phenolic and aliphatic groups and carboxylic acids present in the polymer.…”

Section: Lignin Structurementioning

confidence: 99%

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Hydrolysis efficiency and enzyme adsorption on steam-pretreated spruce in the presence of poly(ethylene glycol)

Sipos

Dienes

Schleicher

et al. 2010

Enzyme and Microbial Technology

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a b s t r a c tEnzymatic hydrolysis of lignocellulosic substrates is one of the limiting steps in second generation bioethanol production. The effects of addition of poly(ethylene glycol) 4000 (PEG) on the efficiency and adsorption of cellulase components during the 72-h hydrolysis of steam-pretreated spruce were investigated. It was found that addition of PEG increased the amount of the enzyme components in the hydrolysis supernatant to varying degrees. As an effect of PEG addition the concentration of free proteins increased by 36% and the free overall cellulolytic activity (FPA) in the liquid fraction by 51%. After 72-h hydrolysis with PEG 48-68% higher activities towards 4-methylumbelliferyl-saccharide substrates were recovered. The results suggest that the effect of PEG is based on the decrease of non-productive enzyme binding. The structure of the hydrolysis residues was studied by 31 P NMR.

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Section: Lignin Structurementioning

confidence: 86%

Section: Lignin Structurementioning

confidence: 99%

Hydrolysis efficiency and enzyme adsorption on steam-pretreated spruce in the presence of poly(ethylene glycol)

Sipos

Dienes

Schleicher

et al. 2010

Enzyme and Microbial Technology

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show abstract

“…The initial assumption was that this fraction should more closely resembles the lignin rich fraction remaining after enzymatic hydrolysis (Berlin et al, 2006;Furuno et al, 2006;Jaaskelainen et al, 2003;Nakagame et al, 2010). Alternatively, rather than using proteases to remove any bound protein, the cellulolytic enzyme lignin (CEL) was obtained by extensive enzymatic hydrolysis followed by extraction with aqueous dioxane.…”

Section: Introductionmentioning

confidence: 99%

Enhancing the enzymatic hydrolysis of lignocellulosic biomass by increasing the carboxylic acid content of the associated lignin

Nakagame

Chandra

Kadla

et al. 2010

Biotech & Bioengineering

228

137

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To assess the effects that the physical and chemical properties of lignin might have on the enzymatic hydrolysis of pretreated lignocellulosic substrates, protease treated lignin (PTL) and cellulolytic enzyme lignin (CEL) fractions, isolated from steam and organosolv pretreated corn stover, poplar, and lodgepole pine, were prepared and characterized. The adsorption of cellulases to the isolated lignin preparations corresponded to a Langmuir adsorption isotherm. It was apparent that, rather than the physical properties of the isolated lignin, the carboxylic acid functionality of the isolated lignin, as determined by FTIR and NMR spectroscopy, had much more of an influence when lignin was added to typical hydrolysis of pure cellulose (Avicel). An increase in the carboxylic content of the lignin preparation resulted in an increased hydrolysis yield. These results suggested that the carboxylic acids within the lignin partially alleviate non-productive binding of cellulases to lignin. To try to confirm this possible mechanism, dehydrogenative polymers (DHP) of monolignols were synthesized from coniferyl alcohol (CA) and ferulic acid (FA), and these model compounds were added to a typical enzymatic hydrolysis of Avicel. The DHP from FA, which was enriched in carboxylic acid groups compared with the DHP from CA, adsorbed a lower mount of cellulases and did not decrease hydrolysis yields when compared to the DHP from CA, which decreased the hydrolysis of Avicel by 8.4%. Thus, increasing the carboxylic acid content of the lignin seemed to significantly decrease the non-productive binding of cellulases and consequently increased the enzymatic hydrolysis of the cellulose.

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“…[5] Lignin isolated by cellulase is more representative of the native lignin, but contains large amounts of residual carbohydrates [6] since cellulase and hemicellulase enzymes retain the bonds between lignin and carbohydrates. [7] The economic feasibility of these new hydrolysis technologies would be enhanced by the development of high value applications for the hydrolysis lignin. [8] Pyrolysis could exploit the potential of lignin to produce highvalue chemicals, although current fast pyrolysis technologies have been developed and optimized for whole biomass.…”

Section: Introductionmentioning

confidence: 99%

Effect of bed material, lignin content, and origin on the processability of biomass in fast pyrolysis reactors

2017

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Lignin has great potential for the production of valuable aromatic compounds and has attracted considerable attention. The development of high value applications for Kraft lignin would boost the profitability of pulp and paper operations. A potential solution is the pyrolytic conversion of lignin to valuable liquids and solids. However, Kraft lignin is a thermally sensitive powder which tends to agglomerate under pyrolysis conditions. A mechanically fluidized reactor (MFR) can be used to monitor both the generation of vapours and gas during pyrolysis and how cohesive a feedstock becomes when pyrolyzed. The MFR was, therefore, used to evaluate alternative solutions to improve Kraft lignin behaviour by mixing it with nonproblematic feedstocks or by modifying its bed material. Finally, Kraft lignin behaviour and products were compared to those of hydrolysis lignins from different origins.

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The effect of isolation method on the chemical structure of residual lignin

Cited by 111 publications

References 9 publications

Hydrolysis efficiency and enzyme adsorption on steam-pretreated spruce in the presence of poly(ethylene glycol)

Hydrolysis efficiency and enzyme adsorption on steam-pretreated spruce in the presence of poly(ethylene glycol)

Enhancing the enzymatic hydrolysis of lignocellulosic biomass by increasing the carboxylic acid content of the associated lignin

Effect of bed material, lignin content, and origin on the processability of biomass in fast pyrolysis reactors

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