Estimation of Aromatic Structure Contents in Hardwood Lignins from IR Absorption Spectra

Derkacheva, O. Yu.

doi:10.1007/s10812-013-9825-1

Cited by 18 publications

(9 citation statements)

References 14 publications

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“…However, syringol, 4-methylsyringol, 4-allysyringol, 3-methoxycatechol and 4-methylguaiacol, were the most representative phenolic compounds found for WL. As can be observed in Table 2, HL was mainly based on guaiacyl units with very small amount of syringyl units, while WL presented more similar monomeric composition to those found for hardwood lignins [41], with 53.2% of syringyl derivatives and 32.2% of guaiacyl-derived compounds detected in the pyrogram. Although syringyl and guaiacyl-type compounds were dominant in both pyrogram, accounting more than 85% of the total peaks, phenol-type and catechol-type compounds were also detected.…”

Section: Chemical Composition and Molecular Properties Of Lignins Fromentioning

confidence: 53%

Lignins from Agroindustrial by-Products as Natural Ingredients for Cosmetics: Chemical Structure and In Vitro Sunscreen and Cytotoxic Activities

2020

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The growing concern about the environmental impact and human health risk related to the excessive use of synthetic ingredients in cosmetics and topical formulations calls for the exploration of safe and sustainable natural alternatives. Lignin-rich lignocellulosic industrial wastes such as hazelnut and walnut shells were used as a lignin polymer source. Agro-derived lignins were evaluated as a potential natural active ingredient for health care products. Aside from the structural characteristics of isolated lignins, which were identified by GPC, Py-GC–MS, and 2D HSQC NMR techniques, functional properties such as antioxidant power and UV absorption ability were investigated. The SPF values found for creams containing 5% of hazelnut and walnut lignin content were 6.9 and 4.5, respectively. Additionally, both lignin types presented appropriate protection against UVA radiation, highly interesting property to block the full ultraviolet spectrum. The biological activity of isolated lignins assessed at different concentrations (0.01–1 mg/mL) and different times (24, 48, and 72 h) on murine fibroblast cell line 3T3 suggested their suitability for cosmetic applications.

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Section: Chemical Composition and Molecular Properties Of Lignins Fromentioning

confidence: 53%

Lignins from Agroindustrial by-Products as Natural Ingredients for Cosmetics: Chemical Structure and In Vitro Sunscreen and Cytotoxic Activities

2020

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“…Attenuated total reflectance—Fourier Transform Infrared (ATR-FTIR) spectroscopy has also been used to estimate monolignols ratios, although it has been done in different ways in different studies [ 40 – 43 ]. Py-GC–MS and NMR are more commonly used to assess S / G ratio [ 38 , 44 ].…”

Section: Resultsmentioning

confidence: 99%

Lignin from hydrothermally pretreated grass biomass retards enzymatic cellulose degradation by acting as a physical barrier rather than by inducing nonproductive adsorption of enzymes

Djajadi

Jensen

Oliveira

et al. 2018

Biotechnol Biofuels

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BackgroundLignin is known to hinder efficient enzymatic conversion of lignocellulose in biorefining processes. In particular, nonproductive adsorption of cellulases onto lignin is considered a key mechanism to explain how lignin retards enzymatic cellulose conversion in extended reactions.ResultsLignin-rich residues (LRRs) were prepared via extensive enzymatic cellulose degradation of corn stover (Zea mays subsp. mays L.), Miscanthus × giganteus stalks (MS) and wheat straw (Triticum aestivum L.) (WS) samples that each had been hydrothermally pretreated at three severity factors (log R0) of 3.65, 3.83 and 3.97. The LRRs had different residual carbohydrate levels—the highest in MS; the lowest in WS. The residual carbohydrate was not traceable at the surface of the LRRs particles by ATR-FTIR analysis. The chemical properties of the lignin in the LRRs varied across the three types of biomass, but monolignols composition was not affected by the severity factor. When pure cellulose was added to a mixture of LRRs and a commercial cellulolytic enzyme preparation, the rate and extent of glucose release were unaffected by the presence of LRRs regardless of biomass type and severity factor, despite adsorption of the enzymes to the LRRs. Since the surface of the LRRs particles were covered by lignin, the data suggest that the retardation of enzymatic cellulose degradation during extended reaction on lignocellulosic substrates is due to physical blockage of the access of enzymes to the cellulose caused by the gradual accumulation of lignin at the surface of the biomass particles rather than by nonproductive enzyme adsorption.ConclusionsThe study suggests that lignin from hydrothermally pretreated grass biomass retards enzymatic cellulose degradation by acting as a physical barrier blocking the access of enzymes to cellulose rather than by inducing retardation through nonproductive adsorption of enzymes.Electronic supplementary materialThe online version of this article (10.1186/s13068-018-1085-0) contains supplementary material, which is available to authorized users.

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“…The S/G ratio has been demonstrated to be an important factor when defining biomass recalcitrance. The reactivity of the G aromatic ring is lower than that of the S one (Derkacheva, 2013), and thus, higher delignification yields after pretreatment could be obtained from biomasses that contain more S than G (Lupoi et al 2015). Perez-Pimienta et al (2016) reported that the S/G ratio of untreated agave bagasse was 4.3, which was considerably higher than that of untreated birch (2.4) (Derkacheva 2013).…”

Section: Nades Pretreatment and Acid-chlorite Delignificationmentioning

confidence: 99%

NADES-based fractionation of biomass to produce raw material for the preparation of cellulose acetates

et al. 2020

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Waste biomass (agave bagasse) and native birch wood were used as raw materials for a novel fractionation and derivation process to produce cellulose acetates (CAs). During the first stage of the fractionation process, a significant amount of hemicelluloses and lignin were dissolved from the biomass using a natural deep eutectic solvent (NADES) that consisted of a mixture of choline chloride and lactic acid with the molar ratio of 1:9. Then, the residual solid material was delignified by bleaching it with a mixture of acetic acid and sodium chlorite. The fractionation process generated differently purified pulps (celluloses) which were converted to CAs. The crystallinity index, polymerization degree, chemical composition, and thermal properties of the differently purified pulps and CAs were analyzed to evaluate the efficacy of the acetylation process and to characterize the CAs. The chemical derivation of the differently purified cellulose samples generated CAs with different degrees of substitution (DSs). The more purified the cellulose sample was, the higher its DS was. Moreover, some differences were observed between the acetylation efficiencies of birch and agave bagasse. Typically, cellulose purified from birch by treating it with NADES followed by bleaching was acetylated more completely (DS = 2.94) than that derived from agave bagasse (DS = 2.45). These results revealed that using green solvents, such as NADES, to treat both agave bagasse (waste biomass) and birch wood, allowed pure fractions to be obtained from biomass, and thus, biomass could be valorized into products such as CAs, which present a wide range of applications.

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Estimation of Aromatic Structure Contents in Hardwood Lignins from IR Absorption Spectra

Cited by 18 publications

References 14 publications

Lignins from Agroindustrial by-Products as Natural Ingredients for Cosmetics: Chemical Structure and In Vitro Sunscreen and Cytotoxic Activities

Lignins from Agroindustrial by-Products as Natural Ingredients for Cosmetics: Chemical Structure and In Vitro Sunscreen and Cytotoxic Activities

Lignin from hydrothermally pretreated grass biomass retards enzymatic cellulose degradation by acting as a physical barrier rather than by inducing nonproductive adsorption of enzymes

NADES-based fractionation of biomass to produce raw material for the preparation of cellulose acetates

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