Role of paramagnetic polyconjugated clusters in lignin antioxidant activity (in vitro)

Using physico-chemical methods (EPR, SEC, Py-GC/MS and UV/VIS spectroscopy) and wet chemical analysis, the characteristics of 6 hardwood lignins in terms of functionality, molecular weight and composition of lignin substructures were determined and considered together with the results of DPPH•, ABTS •+ and O2•- antioxidant assays with the aim to understand the relationships governing antioxidant properties of lignin. The strong positive linear correlation between lignin antioxidant capacity in the three assays used and the extent of conjugation of paramagnetic polyconjugated clusters in lignin macromolecules was found. The biological activity of the most active alkaline lignins was assessed by in vitro experiment with human blood.publishersversionPeer reviewe

Use Of Plants To Remediate Soil Polluted With Oil

In the present investigation the growing and development ability of various annual and perennial plants to grow on model peat substrate artificially polluted with oil products in the range of concentrations from 1 to 5% was evaluated. The highest tolerance towards peat contamination by oil products has been demonstrated by three annual crops (maize, oat and lupine). These plants were tested for phytoremediation of polluted black soil from the area of oil refinery plant (Mazeikiai, Lithuania), which was treated by association of oil oxidizing bacteria up to residual concentration of the oil products of 4.5 %. The maize plants revealed the highest remediation ability: oil content in the soil decreased by ~ 1.5 times in one month plant vegetation

Applications of lignin in the agri-food industry

Of late, valorization of agri-food industrial by-products and their sustainable utilization is gaining much contemplation world-over. Globally, 'Zero Waste Concept' is promoted with main emphasis laid towards generation of minimal wastes and maximal utilization of plantbased agri-food raw materials. One of the wastes/by-products in the agri-food industry are the lignin, which occurs as lignocellulosic biomass. This biomass is deliberated to be an environmental pollutant as they offer resistance to natural biodegradation. Safe disposal of this biomass is often considered a major challenge, especially in low-income countries. Hence, the application of modern technologies to effectively reduce these types of wastes and maximize their potential use/applications is vital in the present day scenario. Nevertheless, in some of the high-income countries, attempts have been made to efficiently utilize lignin as a source of fuel, as a raw material in the paper industry, as a filler material in biopolymer based packaging and for producing bioethanol. However, as of today, agri-food industrial applications remains significantly underexplored. Chemically, lignin is heterogeneous, bio-polymeric, polyphenolic compound, which is present naturally in plants, providing mechanical strength and rigidity. Reports are available wherein purified lignin is established to possess therapeutic values; and are rich in antioxidant, anti-microbial, anti-carcinogenic, antidiabetic properties, etc. This chapter is divided into four sub-categories focusing on various technological aspects related to isolation and characterization of lignin; established uses of lignin; proved bioactivities and therapeutic potentials of lignin, and finally on identifying the existing research gaps followed by future recommendations for potential use from agri-food industrial wastes.Theme of this chapter is based on our ongoing project- Valortech, which has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 810630

Production of nanoporous carbons from wood processing wastes and their use in supercapacitors and CO2 capture

Highly porous carbons were obtained from solid wastes generated in the chemical and the mechanical processing of birch wood (substandard kraft cellulose, hydrolysis lignin, chips and bark). NaOH-chemical activation of these residues at 575–800 °C resulted in an efficient process to produce carbons with specific surface areas well above 1000 m2 g−1 and average pore widths of 1–1.7 nm. Comparative evaluations have shown the potentiality of wood wastes-based carbons in applications related to environmental protection. Activated carbons derived from chips- and bark-birch wood displayed specific capacitances as high as 308 F g−1 in the H2SO4 aqueous electrolyte and 200 F g−1 in the (C2H5)4NBF4/acetonitrile organic medium. Moreover, their capacitive performance at high current density competed well with that found for commercial carbons used in supercapacitors. Wood-derived carbons also proved to be highly promising for CO2 capture in power stations, achieving uptakes under post- and pre-combustion conditions of 11–16 wt.% and 49–91 wt.%, respectively.The research leading to these results has received funding support of the European Community’s Service Framework Programme (FP7/2007-2011,203459), from the Latvian Budget (Grant 1546), and the Latvian National Programme VPP-2,2.4,1.1.Peer reviewe

Tannins of Deciduous Trees Bark as a Potential Source for Obtaining Ecologically Safe Wood Adhesives

The bark of deciduous trees grown in Latvia: grey alder, black alder, ash tree and goat willow were sequentially extracted using solvents of increasing polarity. The data about total content of both lipophilic and hydrophilic compounds were obtained using sequentially extraction with hexane and ethanol. The highest yields of hydrophilic extractives were found for grey alder and ash tree barks (25.7% and 25.8%, respectively). Hydrophilic extract from the both alder species contained high amount (up to 12% on bark dry mass) of condensed tannins (CT) or oligomeric proanthocyanidins, whereas CT content of extract from ach tree was negligible. The main component of ethanol-water extract from alder bark was identified using 13C NMR and MALDI–TOF MS spectroscopy as a mixture of A- and B-type oligomeric procyanidins with the epicatechin units polymerization degree of 2-7. Ecologically friendly wood adhesives were obtained on the condensed tannin basis

Isolation and Characterisation of the Phenolic Fractions of Wood Pyrolytic Oil

A fraction of pyrolytic oils (PyO) – obtained by fast pyrolysis of alder (Alnus incana), ash-tree (Fraxinus excelsior) and aspen (Populus tremula) in a laboratory scale reactor – was precipitated in water. This hydrophobic moiety of PyO is called pyrolytic lignin (PyL). The composition of the volatile monomeric compounds of PyO and the PyL fraction was determined by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). It has been found that PyL has a high content of phenolic products (between 75% and 83%), which varies depending on the wood species. The antioxidant properties of the PyL fraction were studied and it was demonstrated that the antioxidant activity determined in different tests exceeded the corresponding activity of alkali lignin. The antioxidant properties of PyL are on the same level as those of the widely used antioxidants, such as rutin, trolox, curcumine, and tert-butylhydroquinone (TBHQ). A new method was developed for the extraction of a monomeric phenol fraction (Py-monPh) from PyO by means of the organic solvent methyl tert-butyl ether (MTBE). The Py-monPh can be considered as a promising source of antioxidants

Characterization of Bark Rich-In-Tannins Extracts from Deciduous Trees with Emphasis on Their Antioxidant Activity

The barks of deciduous trees spread over a wide area of Northern Europe, were sequentially extracted using solvents of increasing polarity. The highest yields of hydrophilic extractives were found for ash tree and goat willow (23.6% and 23.8%, respectively). The highe st total contents of polyphenols were found for black alder and goat willow bark (0.18 GAE  g -1 and 0.12 GAE  g -1 , respectively). Hydrophilic extract from the both grey and black alder barks contained high amount (up to 7 % on bark dry mass) of condensed tannins (CT) or oligomeric proanthocyanidins (OPC). In tests with free radicals (ABTS ●+ , DPPH ● ), the high radical scavenging capacities of the hydrophilic extracts enriched with OPC were demonstrated. The antioxidant efficiency of the hydrophilic extracts and purified OPC from alder barks was tested by their influence on thermo-oxidative destruction of model polyurethane (PU) films. The hydrophilic extracts enriched with tannins have good potential as a technical antioxidant for polyurethanes, with the most prominent activity for the hydrophilic extract from black alder and goat willow bark

Functionality and physico-chemical characteristics of wheat straw lignin, BioligninTM, derivatives formed in the oxypropylation process

The new organosolv process of wheat straw fractionation elaborated by Compagnie Industrielle de la matiere Vegetale (France) corresponds to the biorefinery approach, which allows separating cellulose, hemicel -luloses, and lignin. The straw lignin (Biolignin) is an attractive product, for which new applications are sought. In the present work, straw lignin (L) was converted into liquid lignopolyols via a batch reaction with propylene oxide (PO). The effects of the lignin content (L%) in the initial reaction mixture (L/(L+PO) on the oxypropylation process and the properties of whole lignopolyols and L/PO copolymers were studied. Almost complete disappearance of L-OHphen and L-COOH groups in copolymers was accompanied by an increase in the L-OHaliph groups’ content therein. The polydispersity (Mw/Mn) of all copolymers obtained decreased essentially compared to the reference. The extent of PO grafting onto OH groups increased with decreasing lignin content in the initial reaction mixture. At a lignin content of 15–30% in the initial reaction mixture, the lignopolyols fulfil the requirements of polyol polyethers for rigid polyurethane foam production. The further increase in the lignin content leads to the appearance of the non-liquefied fraction and the undesirable increase in the viscosity of the liquefied part