Characterization of Softwood and Hardwood LignoBoost Kraft Lignins with Emphasis on their Antioxidant Activity

Ponomarenko, Jevgenija; Dizhbite, Tatiana; Lauberts, Māris; Vīksna, Artūrs; Dobele, Gaļina; Bikovens, Oskars; Телышева, Галина

doi:10.15376/biores.9.2.2051-2068

Cited by 71 publications

(64 citation statements)

References 22 publications

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“…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%

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: Introductionmentioning

confidence: 99%

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

et al. 2019

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“…Fractionation of lignin in organic solvents or alcohols has been employed to improve the miscibility of lignin with other polymers and as well as to obtain extracts with high antioxidant activity . Fractionation in alcohol enables the extraction of lignin of specific MWs and a high phenolic hydroxyl content.…”

Section: Introductionmentioning

confidence: 99%

Mechanical, thermal, and antioxidant properties of composite films prepared from durum wheat starch and lignin

et al. 2015

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Lignin conveys several important and useful characteristics to starch films depending on the lignin MW, extraction procedure, and lignin botanical source. In this study, lignin was obtained from durum wheat straw through the organosolv process, followed by fractionation according to solubility in alcohol. The alcohol-soluble lignin (ASL) was then used to prepare starch-ASL films. The mechanical properties, thermal stability, water solubility, color, and antioxidant activity of the resulting films were evaluated, and the starch-ASL films were also analyzed by means of SEM and attenuated total reflection infrared spectroscopy (ATR-IR). A procedure, to incorporate ASL, was developed and used to produce homogenous surfaces in starch-ASL films; agglomerations or undissolved particles of lignin were not observed in the starch matrix at microscopic level. ASL promoted significant decrease of the tensile strength (TS) and elastic modulus (EM), but an increase of elongation at break (EB) in films. Thermal analysis of the starch-ASL films showed high resistance to thermal degradation, due to the incorporation of ASL. In addition, the starch-ASL films exhibited antioxidant activity (2,2-diphenyl-1-picrylhydrazyl [DPPH]), which increased with increasing ASL content.

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“…The high content of methoxylated phenyl units in lignin may have a positive effect on its antioxidant activity and CH 2 groups in the α-position of the phenols aromatic ring Ar-CH 3 (ArC 1 ), Ar-CH 2 -CH 3 (ArC 2 ), Ar-CH 2 -CH 2 -CH 3 (ArC 3 ) can also increase the antioxidant activity of lignins due to their electron-donating properties (Ponomarenko et al 2014(Ponomarenko et al , 2015. Furthermore, the high ratio between the summed portion of phenols with shortened side chains (ArC 1 +ArC 2 ) and phenols with propanoid side chain (ArC 3 ) in the lignin pyrolysis products has a strong positive impact on lignin antioxidant activity.…”

Section: Resultsmentioning

confidence: 99%

“…Selective precipitation and ultrafiltration are potentially useful techniques, depending on the intended lignin application (Brodin et al 2009;Toledano et al 2010;Ponomarenko et al 2014;Sevastyanova et al 2014;Duval et al 2015). It has been demonstrated that an increased content of OH aliph and OH phen groups improves the acetone solubility of lignin, which would be beneficial for fractionation based on acetone and hexane (Cui et al 2014).…”

Section: Resultsmentioning

confidence: 99%

COST Action FP1105: effect of raw materials and pulping conditions on the characteristics of dissolved kraft lignins

et al. 2016

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Abstract:The composition, molecular weight (MW), and chemical structure of technical lignins as byproducts of pulping influence their application in terms of physical and chemical properties, reactivity, and performance. It is important to know how the analytical data of technical lignins are influenced by the wood species and the parameters of pulping. The present study focuses on kraft pulping and how the wood species (eucalyptus, pine, and spruce) and variable cooking times influence the characteristics of dissolved lignins. The black liquor (BL) was recovered after three different cooking times and the precipitated lignin was characterized by total acid hydrolysis including the determination of the acid insoluble part (Klason lignin, KL) and the sugars in the hydrolysate, elemental analysis, 31 P NMR spectroscopy, analytical pyrolysis (Py-GC/MS), gel permeation chromatography (GPC), thermogravimetry (TG), and differential scanning calorimetry (DSC). The results indicate that the phenolic OH content, MW and glass transition temperature increased with longer cooking times for the softwood (SW) lignins. These lignins had also a higher MW (M w 5500-8000 g mol -1 ), than the eucalyptus lignin (M w 2200-2400 g mol -1 ). Eucalyptus lignin had higher sulfur content compared to SW.

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Characterization of Softwood and Hardwood LignoBoost Kraft Lignins with Emphasis on their Antioxidant Activity

Cited by 71 publications

References 22 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

Mechanical, thermal, and antioxidant properties of composite films prepared from durum wheat starch and lignin

COST Action FP1105: effect of raw materials and pulping conditions on the characteristics of dissolved kraft lignins

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