Fractionation and characterization of lignins from Miscanthus via organosolv and soda pulping for biorefinery applications

Kim, Ga-Hee; Um, Byung-Hwan

doi:10.1016/j.ijbiomac.2020.04.229

Cited by 37 publications

(12 citation statements)

References 40 publications

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“…The different yields obtained confirm that we are testing our methodologies on different lignin types that exhibit different dissolution characteristics. The proportions of acid-soluble and -insoluble lignins, carbohydrates and ash for both lignins were broadly similar to those reported previously by us 43 , 62 and others 63 . The Indulin AT lignin possessed a slightly lower acid-soluble lignin (ASL) content (0.5 wt %, compared with 1.9% found previously 43 ), but in common with previous studies 43 , 62 , soda lignin P1000 possessed higher ASL (~ 5%) compared with those reported previously for other similar alkaline lignins such as straw, hemp, flax and hardwood-derived lignins (0.4–0.9%) 22 and wheat straw (1.0–1.1%) 64 .…”

Section: Resultssupporting

confidence: 90%

Characterisation of mass distributions of solvent-fractionated lignins using analytical ultracentrifugation and size exclusion chromatography methods

Joosten

Donkers

et al. 2021

Sci Rep

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Lignins are valuable renewable resources for the potential production of a large array of biofuels, aromatic chemicals and biopolymers. Yet native and industrial lignins are complex, highly branched and heterogenous macromolecules, properties that have to date often undermined their use as starting materials in lignin valorisation strategies. Reliable knowledge of weight average molar mass, conformation and polydispersity of lignin starting materials can be proven to be crucial to and improve the prospects for the success of such strategies. Here we evaluated the use of commonly-used size exclusion chromatography (SEC)—calibrated with polystyrene sulphonate standards—and under-used analytical ultracentrifugation—which does not require calibration—to characterise a series of lignin fractions sequentially extracted from soda and Kraft alkaline lignins using ethyl acetate, methyl ethyl ketone (MEK), methanol and acetone:water (fractions F01–F04, respectively). Absolute values of weight average molar mass (Mw) determined using sedimentation equilibrium in the analytical ultracentrifuge of (3.0 ± 0.1) kDa and (4.2 ± 0.2) kDa for soda and Kraft lignins respectively, agreed closely with previous SEC-determined Mws and reasonably with the size exclusion chromatography measurements employed here, confirming the appropriateness of the standards (with the possible exceptions of fraction F05 for soda P1000 and F03 for Indulin). Both methods revealed the presence of low (~ 1 kDa) Mw material in F01 and F02 fractions followed by progressively higher Mw in subsequent fractions. Compositional analysis confirmed > 90% (by weight) total lignins successively extracted from both lignins using MEK, methanol and acetone:water (F02 to F04). Considerable heterogeneity of both unfractionated and fractionated lignins was revealed through determinations of both sedimentation coefficient distributions and polydispersity indices. The study also demonstrates the advantages of using analytical ultracentrifugation, both alongside SEC as well as in its own right, for determining absolute Mw, heterogeneity and conformation information for characterising industrial lignins.

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Section: Resultssupporting

confidence: 90%

Characterisation of mass distributions of solvent-fractionated lignins using analytical ultracentrifugation and size exclusion chromatography methods

Joosten

Donkers

et al. 2021

Sci Rep

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“…For example, the whole crop application includes direct power generation, fuel production, as well as components for fiber-based hybrid materials such as lightweight concrete [10,[67][68][69]. Moreover, cascading use of Miscanthus is reported using the biomass successively in integrated processes.…”

Section: Resultsmentioning

confidence: 99%

Lignins Isolated via Catalyst-free Organosolv Pulping from Miscanthus x giganteus, M. sinensis, M. robustus and M. nagara: A Comparative Study

Schulze¹,

Bergs²,

Monakhova³

et al. 2021

Preprint

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As a low-input crop, Miscanthus offers numerous advantages that, in addition to agricultural applications, permits its exploitation for energy, fuel, and material production. Depending on the Miscanthus genotype, season, and harvest time as well as plant component (leaf versus stem), correlations between structure and properties of the corresponding isolated lignins differ. Here, a comparative study is presented between lignins isolated from M. x giganteus, M. sinensis, M. robustus and M. nagara using a catalyst-free organosolv pulping process. The lignins from different plant constituents are also compared regarding their similarities and differences regarding monolignol ratio and important linkages. Results showed that the plant genotype has the weakest influence on monolignol content and interunit linkages. In contrast, structural differences are more significant among lignins of different harvest time and/or season. Analyses were performed using fast and simple methods such as nuclear magnetic resonance (NMR) spectroscopy. Data was assigned to four different linkages (A: b-O-4 linkage, B: phenylcoumaran, C: resinol, D: b-unsaturated ester). In conclusion, A content is particularly high in leaf-derived lignins at just under 70 % and significantly lower in stem and mixture lignins at around 60 % and almost 65 %. The second most common linkage pattern is D in all isolated lignins, the proportion of which is also strongly dependent on the crop portion. Both stem and mixture lignins, have a relatively high share of approximately 20 % or more (maximum is M. sinensis Sin2 with over 30 %). In the leaf-derived lignins, the proportions are significantly lower on averageStem samples should be chosen highest possible lignin content is desired, specifically from the M. x giganteus genotype which revealed lignin contents up to 27 %.

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“…Further processing of the already relatively low molecular weight lignin fragments into more defined structures also makes lignin extraction from miscanthus significantly more attractive, for example for applications as bioactive additive in active packaging and medicine. For example, the whole crop application includes direct power generation, fuel production, as well as components for fiber-based hybrid materials such as lightweight concrete [10,[69][70][71]. Moreover, cascading use of Miscanthus is reported using the biomass successively in integrated processes.…”

Section: Discussionmentioning

confidence: 99%

Lignins Isolated via Catalyst-Free Organosolv Pulping from Miscanthus x giganteus, M. sinensis, M. robustus and M. nagara: A Comparative Study

Bergs

Monakhova

Diehl³

et al. 2021

Molecules

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As a low-input crop, Miscanthus offers numerous advantages that, in addition to agricultural applications, permits its exploitation for energy, fuel, and material production. Depending on the Miscanthus genotype, season, and harvest time as well as plant component (leaf versus stem), correlations between structure and properties of the corresponding isolated lignins differ. Here, a comparative study is presented between lignins isolated from M. x giganteus, M. sinensis, M. robustus and M. nagara using a catalyst-free organosolv pulping process. The lignins from different plant constituents are also compared regarding their similarities and differences regarding monolignol ratio and important linkages. Results showed that the plant genotype has the weakest influence on monolignol content and interunit linkages. In contrast, structural differences are more significant among lignins of different harvest time and/or season. Analyses were performed using fast and simple methods such as nuclear magnetic resonance (NMR) spectroscopy. Data was assigned to four different linkages (A: β-O-4 linkage, B: phenylcoumaran, C: resinol, D: β-unsaturated ester). In conclusion, A content is particularly high in leaf-derived lignins at just under 70% and significantly lower in stem and mixture lignins at around 60% and almost 65%. The second most common linkage pattern is D in all isolated lignins, the proportion of which is also strongly dependent on the crop portion. Both stem and mixture lignins, have a relatively high share of approximately 20% or more (maximum is M. sinensis Sin2 with over 30%). In the leaf-derived lignins, the proportions are significantly lower on average. Stem samples should be chosen if the highest possible lignin content is desired, specifically from the M. x giganteus genotype, which revealed lignin contents up to 27%. Due to the better frost resistance and higher stem stability, M. nagara offers some advantages compared to M. x giganteus. Miscanthus crops are shown to be very attractive lignocellulose feedstock (LCF) for second generation biorefineries and lignin generation in Europe.

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Fractionation and characterization of lignins from Miscanthus via organosolv and soda pulping for biorefinery applications

Cited by 37 publications

References 40 publications

Characterisation of mass distributions of solvent-fractionated lignins using analytical ultracentrifugation and size exclusion chromatography methods

Characterisation of mass distributions of solvent-fractionated lignins using analytical ultracentrifugation and size exclusion chromatography methods

Lignins Isolated via Catalyst-free Organosolv Pulping from Miscanthus x giganteus, M. sinensis, M. robustus and M. nagara: A Comparative Study

Lignins Isolated via Catalyst-Free Organosolv Pulping from Miscanthus x giganteus, M. sinensis, M. robustus and M. nagara: A Comparative Study

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