Miscanthus x giganteus Stem Versus Leaf-Derived Lignins Differing in Monolignol Ratio and Linkage

Bergs, Michel; Völkering, Georg; Kraska, Thorsten; Pude, Ralf; Tung, Xuan; Kusch, Peter; Monakhova, Yulia B.; Konow, Christopher; Schulze, Margit

doi:10.3390/ijms20051200

Cited by 33 publications

(73 citation statements)

References 90 publications

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“…The filter cake was washed with distilled water and sulfuric acid (25 vol.%) until the requested pH value was reached (pH 2 to pH 5). Finally, the precipitated lignin was dried in a freeze dryer for 48 h. The organosolv lignin (OL) was isolated according to a procedure recently reported [10].…”

Section: Extraction Of Kraft Lignin (Kl) and Organosolv Lignin (Ol)mentioning

confidence: 99%

“…The log 10 -reduction is a measure for the antimicrobial activity and effectiveness of the coatings. According to the JIS a material is called antimicrobial when the log 10 -reduction is ≥2 log 10 .…”

Section: Antimicrobial Activity Of the Lpu Coatingsmentioning

confidence: 99%

“…Lignin, the most abundant natural resource next to cellulose and hemicellulose [1][2][3][4] contains various functional groups that provide active sites for chemical modification such as polarity adjustment to enhance the compatibility of lignin with other polymeric matrices in lignin/polymer composites [4,5] or to improve antioxidant properties [6][7][8][9][10][11]. Furthermore, studies reported lignin-derived encapsulation of various drugs for biomedical and agricultural applications.…”

Section: Introductionmentioning

confidence: 99%

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Antimicrobial Activity of Lignin-Derived Polyurethane Coatings Prepared from Unmodified and Demethylated Lignins

et al. 2019

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Due to global ecological and economic challenges that have been correlated to the transition from fossil-based to renewable resources, fundamental studies are being performed worldwide to replace fossil fuel raw materials in plastic production. One aspect of current research is the development of lignin-derived polyols to substitute expensive fossil-based polyol components for polyurethane and polyester production. This article describes the synthesis of bioactive lignin-based polyurethane coatings using unmodified and demethylated Kraft lignins. Demethylation was performed to enhance the reaction selectivity toward polyurethane formation. The antimicrobial activity was tested according to a slightly modified standard test (JIS Z 2801(JIS Z :2010. Besides effects caused by the lignins themselves, triphenylmethane derivatives (brilliant green and crystal violet) were used as additional antimicrobial substances. Results showed increased antimicrobial capacity against Staphylococcus aureus. Furthermore, the coating color could be varied from dark brown to green and blue, respectively.Coatings 2019, 9, 494 2 of 16 and DNA in cells of mice against oxidation damage [19] have been tested. Gao [20] and Bshena [21] studied the antimicrobial activity of various textiles, using lignin incorporated into polyethylene films and applied in the finishing processes. For textiles, there are special requirements such as non-toxicity to the consumer, namely cytotoxicity, allergy or irritation and sensitization. In other recent studies, lignosulfonic acid is reported to exhibit broad-spectrum anti-HIV (human immunodeficiency virus) and anti-HSV (herpes simplex virus) properties [22,23]. Thus, Qiu investigated the anti-HIV-1 activity-potential of lignosulfonates as a microbicide to prevent HIV-1 sexual transmission [23]. Another recently reported study revealed that the antimicrobial capacity of lignin correlates with the phenolic components, specifically the side chain structure and the nature of further functional groups [24]. Typically, the presence of a double bond in α, β positions of the side chain and a methyl group in the γ position grants the phenolic fragments with the most potency against microorganisms. However, none of the hitherto published studies included the investigation of the antibacterial activity of lignin when included in polymeric matrices.Unmodified lignin is widely studied as a component for polymer production with a focus on phenol-formaldehyde resins and polyurethanes (PUs) [25], where lignin is used as polyol substitute due to the high amount of hydroxyl groups resulting in high crosslinking densities and variable mechanical properties [26][27][28]. In previous studies, lignin-derived polyurethane coatings have been prepared using Kraft lignin isolated at room temperature from aqueous media (black liquor) at different pH values [29]. In addition, their antioxidative activity has been investigated using the Folin-Ciocalteu (FC) assay [30]. Although lignin contains many functionalities, they are often diff...

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Section: Extraction Of Kraft Lignin (Kl) and Organosolv Lignin (Ol)mentioning

confidence: 99%

Section: Antimicrobial Activity Of the Lpu Coatingsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Antimicrobial Activity of Lignin-Derived Polyurethane Coatings Prepared from Unmodified and Demethylated Lignins

et al. 2019

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“…Figure 3 shows the most common lignin linkages formed during biosynthesis, some of which having been elucidated within the last five years [23,24]. Table 1 shows average values for monolignol linkages found for hard/soft wood and grasses [25][26][27]. These structural differences are rather difficult to specify by conventional analytical methods using data univariate processing, due to signal overlapping in spectral data.…”

Section: First-and Second-generation Lcf Biorefineriesmentioning

confidence: 99%

“…The RCF procedure combines a lignin catalytic depolymerization with fractionation of the degraded low molecular weight lignin oligomers, or even monomers (i.e., alkylated catechols) [41]. Reprinted from [27] under open access license.…”

Section: First-and Second-generation Lcf Biorefineriesmentioning

confidence: 99%

Low-Input Crops as Lignocellulosic Feedstock for Second-Generation Biorefineries and the Potential of Chemometrics in Biomass Quality Control

et al. 2019

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Lignocellulose feedstock (LCF) provides a sustainable source of components to produce bioenergy, biofuel, and novel biomaterials. Besides hard and soft wood, so-called low-input plants such as Miscanthus are interesting crops to be investigated as potential feedstock for the second generation biorefinery. The status quo regarding the availability and composition of different plants, including grasses and fast-growing trees (i.e., Miscanthus, Paulownia), is reviewed here. The second focus of this review is the potential of multivariate data processing to be used for biomass analysis and quality control. Experimental data obtained by spectroscopic methods, such as nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FTIR), can be processed using computational techniques to characterize the 3D structure and energetic properties of the feedstock building blocks, including complex linkages. Here, we provide a brief summary of recently reported experimental data for structural analysis of LCF biomasses, and give our perspectives on the role of chemometrics in understanding and elucidating on LCF composition and lignin 3D structure.

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Identification and Classification of Technical Lignins by means of Principle Component Analysis and k‐Nearest Neighbor Algorithm

2021

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The characterization of technical lignins is a key step for the efficient use and processing of this material into valuable chemicals and for quality control. In this study 31 lignin samples were prepared from different biomass sources (hardwood, softwood, straw, grass) and different pulping processes (sulfite, Kraft, organosolv). Each lignin was analyzed by attenuated total reflectance Fourier transform infrared (ATR-FT-IR) spectroscopy. Statistical analysis of the ATR-FT-IR spectra by means of principal component analysis (PCA) showed significant differences between the lignins. Hence, the samples can be separated by PCA according to the original biomass. The differences observed in the ATR-FT-IR spectra result primarily from the relative ratios of the p-hydroxyphenyl, guaiacyl and syringyl units. Only limited influence of the pulping process is reflected by the spectral data. The spectra do not differ between samples processed by Kraft or organosolv processes. Lignosulfonates are clearly distinguishable by ATR-FT-IR from the other samples. For the classification a model was created using the k-nearest neighbor (k-NN) algorithm. Different data pretreatment steps were compared for k = 1 … 20. For validation purposes, a 5-fold cross-validation was chosen and the different quality criteria Accuracy (Acc), Error Rate (Err), Sensitivity (TPR) and specificity (TNR) were introduced. The optimized model for k = 4 gives values for Acc = 98.9 %, Err = 1.1 %, TPR = 99.2 % and TNR = 99.6 %.

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Miscanthus x giganteus Stem Versus Leaf-Derived Lignins Differing in Monolignol Ratio and Linkage

Cited by 33 publications

References 90 publications

Antimicrobial Activity of Lignin-Derived Polyurethane Coatings Prepared from Unmodified and Demethylated Lignins

Antimicrobial Activity of Lignin-Derived Polyurethane Coatings Prepared from Unmodified and Demethylated Lignins

Low-Input Crops as Lignocellulosic Feedstock for Second-Generation Biorefineries and the Potential of Chemometrics in Biomass Quality Control

Identification and Classification of Technical Lignins by means of Principle Component Analysis and k‐Nearest Neighbor Algorithm

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