Complex Lignin Research Articles

Computational Advances in Ionic Liquid Applications for Green Chemistry: A Critical Review of Lignin Processing and Machine Learning Approaches.

The valorization and dissolution of lignin using ionic liquids (ILs) is critical for developing sustainable biorefineries and a circular bioeconomy. This review aims to critically assess the current state of computational and machine learning methods for understanding and optimizing IL-based lignin dissolution and valorization processes reported since 2022. The paper examines various computational approaches, from quantum chemistry to machine learning, highlighting their strengths, limitations, and recent advances in predicting and optimizing lignin-IL interactions. Key themes include the challenges in accurately modeling lignin's complex structure, the development of efficient screening methodologies for ionic liquids to enhance lignin dissolution and valorization processes, and the integration of machine learning with quantum calculations. These computational advances will drive progress in IL-based lignin valorization by providing deeper molecular-level insights and facilitating the rapid screening of novel IL-lignin systems.

Urea-lactic acid as efficient lignin solvent and its practical utility in sustainable electrospinning

The development of lignin-based materials presents a promising avenue for advancing green chemistry and mitigating environmental impact. However, the key challenge lies in the processability of lignin, which significantly affects its practical applications. Addressing the issues related to lignin's complex structure, variability, and reactivity is crucial for optimizing its incorporation into high-performance materials. Therefore, in this study we explore the efficacy of a urea-lactic acid-based deep eutectic solvent (ULA) for the dissolution of kraft lignin, aiming to enhance its practical utility in sustainable electrospinning processes, for the first time. Results of elemental analysis, IR and 2D NMR spectroscopy, provide crucial insights into the structural properties of the regenerated material post-DES treatment. The findings confirm a high lignin recovery rate, reaching up to 96.6 % for samples dissolved at 100°C. Additionally, 2D NMR analysis indicates that the process leads to partial esterification of lignin with lactate ions. The ability of the studied DES to effectively solubilize lignin underscores its potential as an efficient lignin solvent and facilitates the fabrication of lignin-based nanofibers via electrospinning. The incorporation of this DES in electrospinning processes promises significant advancements in the development of sustainable, lignin-derived materials and offers a green alternative for production of high-performance nanofibers. Preliminary results of electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements confirm that the EDLC with prepared hydrogel electrolyte demonstrates attractive electrochemical properties (specific capacitance, CSP = 95 F g–1; series resistance RS = 2.2 Ω; charge transfer resistance, RCT = 1.6 Ω), which are comparable with the reference cell based on a commercial glass fibre separator. Hence, the DES-assisted-electrospinned lignin membrane can be viewed as a potential gel electrolyte matrix for practical use in construction of sustainable energy storage devices.

Hydrogen peroxide assisted oxidative liquefaction of alkaline lignin over cobalt-nickel loaded zirconia catalysts

Research toward the oxidative fractionation of lignin is gaining attention due to the selective breaking of a sub-aromatic unit of lignin's complex structure into monomeric phenolic. This study aims to investigate the liquefaction tendency of alkaline lignin by screening the synergistic effect of Co and Ni loaded on synthesized (syn) ZrO2 catalyst under the applied mild oxidative reaction conditions of molecular oxygen and hydrogen peroxide. Compared to the non-catalytic reaction (38.1 wt%), a significant improvement in the bio-oil yield (53.7 wt%) was obtained with the 5Co–5Ni/ZrO2-syn catalyst under the oxidative condition of molecular oxygen. However, only 44.3 wt% bio-oil was observed with commercial (com) 5Co–5Ni/ZrO2-com catalyst. The synergistic study of Co and Ni metal exhibited a diverse impact on the fractionation of lignin into respective product yields (bio-oil, gas, and char). Notably, adding a catalytic amount of hydrogen peroxide showed a remarkable improvement in liquefaction. The maximum bio-oil yield (72.1 wt%), and a maximum conversion (77.9%) were noticed with 0.5 mL H2O2 at 120 °C/30 min under the atmospheric molecular oxygen. The GC-MS analysis of bio-oil (5Co–5Ni/ZrO2-syn-HP) attributed to a high quantity of guaiacyl phenolic with a maximum proportion of benzaldehyde-3-hydroxy-4-methoxy (65.3%). The 5Co–5Ni/ZrO2-syn catalyst was also examined for the three catalytic cycles, which did not show any significant loss in product yield.

Unveiling the ability of protic and aprotic ionic liquids to dissolve and modify Kraft lignin

Lignin, a renewable macromolecule abundant in lignocellulosic biomass, holds significant promise as a renewable source for producing biofuels, biomaterials, and fine chemicals, offering a potential avenue to reduce dependence on petroleum-derived products. However, the lignin complex structure poses challenges for its effective utilization, often requiring some special treatments. In recent decades, ionic liquids (ILs) have been pointed out as promising candidates for lignin processing due to their appealing properties, which include low vapor pressure/flammability, high chemical and thermal stability, and efficacy as lignin solvents. ILs may be categorized as protic (PILs) or aprotic ionic liquids (AILs), and these two classes offer distinct advantages. PILs are readily synthesized by mixing an acid and a base in stoichiometric proportions, forming a mixture containing neutral species that remain in equilibrium with cations and anions. In contrast, AILs present cations with enduring positive charges and are not in equilibrium with their precursors as the PILs, though AILs are frequently more expensive and challenging to produce. Within the biorefinery context, the ability to dissolve Kraft lignin is pivotal for developing new strategies and technologies. Moreover, chemical transformations may occur during lignin dissolution in IL solutions. In this study, the solubility of Kraft lignin was evaluated in four neat imidazolium-based AILs, five neat pyrrolidinium-based PILs, and in aqueous solutions of these ILs, at 313.2 K. The highest solubility value ((77.71 ± 1.03) wt%) was observed for pyrrolidinium octanoate (PIL), while 1-butyl-3-methylimidazolium methyl sulfate exhibited the highest solubility ((73.93 ± 1.27) wt%) among the studied AILs. Whenever possible, the solubilities measured in the present work were critically compared with data available in the literature. Finally, lignin recovered from the IL solutions was analyzed by Gel Permeation Chromatography (GPC), Fourier Transform Infrared (FTIR), and Nuclear Magnetic Resonance (NMR) spectroscopy to assess the solvent ability to induce structural modifications in this macromolecule. The analysis revealed that ILs effectively cleaved β-O-4 linkages in lignin molecules, and concurrent condensation reactions might increase the precipitated lignin molecular weight.

Exploration of the Linkages between Lignin and Carbohydrates in Kraft Pulp from Wheat Straw Using a 13C/2H Isotopic Tracer.

To further our understanding of the change in association between lignin and carbohydrates after kraft pulping, isotope-labeled kraft pulp (KP) was prepared using 13C and D double-isotope-labeled wheat straw, and it was subjected to enzymatic hydrolysis and ionic liquid treatment to explore the linkages between lignin and carbohydrate complexes in wheat straw. Isotope abundance determination showed that 13C and D abundances in the experimental groups were substantially higher than those in the control group, indicating that the injected exogenous coniferin-[α-13C], coniferin-[γ-13C], and d-glucose-[6-D2] were effectively absorbed and metabolized during wheat internode growth. Solid-state CP/MAS 13C-NMR spectroscopy showed that lignin was mainly linked to polysaccharides via acetal, benzyl ether, and benzyl ester bonds. Kraft pulp (KP) from the labeled wheat straw was degraded by cellulase. The obtained residue was fractionated using the ionic liquid DMSO/TBAH to separate the cellulose-lignin complex (KP-CLC) and xylan-lignin complex (KP-XLC). X-ray diffractometer determination showed that the KP-CLC regenerated cellulose type II from type I after the ionic liquid conversion. The 13C-NMR spectrum of Ac-En-KP-CLC showed that the cellulose-lignin complex structure was chemically bonded between the lignin and cellulose through acetal and benzyl ether bonds. The 13C-NMR spectrum of En-KP-XLC showed a lignin-hemicellulose complex structure, wherein lignin and xylan were chemically bonded by benzyl ether and acetal bonds. These results indicate that the cross-linking between lignin and carbohydrates exists in lignocellulosic fibers even after kraft pulping.

Hydrotalcite supported cobalt and tungsten catalysts for valorization of lignin into valuable phenolics

Designing of an efficient catalytic system to break down the sub-aromatic units from the lignin complex 3D structure is a challenging task in biorefinery. Herein, we have designed and prepared the cobalt-impregnated hydrotalcite HT500 basic catalysts for the valorization of an industrial lignin. Catalysts were synthesized using base (e.g., NH3, NaOH) and without the use of the base. The 10 wt% Co/HTNaOH catalyst showed excellent liquefaction tendency by yielding maximum bio-oil (72 wt%) together with high selectivity of acetosyringone under mild reaction conditions (70 °C/3h). This may be owing to the efficient breakage of β-O-4 linkages together with the activation of the Ar-Cα-OH bonds. With the incorporation of W (Co-W/HTNaOH), the selectivity towards acetosyringone was enhanced remarkably (65 area%). The 1H, 13C, and 2D-NMR analysis of raw lignin and bio-oil validate the cleavage of Ar-Cα-OH and ether linkages (β-O-4) without disturbing C–C linkages present in sub-aromatic units of lignin e.g., syringyl and guaiacyl. The Co-W/HTNaOH showed good catalytic performance up to two successive cycles upon regeneration. The XRD, BET, TEM, SEM, XPS, and FT-IR characterization of fresh and regenerated catalysts did not show any significant loss in catalytic active sites, indicating good catalyst regeneration.

Depolymerization of lignin: Recent progress towards value-added chemicals and biohydrogen production

The need for alternative sources of energy became increasingly urgent as demand for energy and the use of fossil fuels both soared. When processed into aromatic compounds, lignin can be utilized as an alternative to fossil fuels, however, lignin's complex structure and recalcitrance make depolymerization impractical. This article presented an overview of the most recent advances in lignin conversion, including process technology, catalyst advancement, and case study-based end products. In addition to the three established methods (thermochemical, biochemical, and catalytic depolymerization), a lignin-first strategy was presented. Depolymerizing different forms of lignin into smaller phenolic molecules has been suggested using homogeneous and heterogeneous catalysts for oxidation or reduction. Limitations and future prospects of lignin depolymerization have been discussed which suggests that solar-driven catalytic depolymerization through photocatalysts including quantum dots offers a unique pathway to obtain the highly catalytic conversion of lignin.

Rigid polyurethane foams refined by the lignin oligomers from catalytic upstream biorefining process

Bio-rigid polyurethane foams (RPFs) were synthesized using the poplar sawdust lignin oligomers that were fractionized by catalytic upstream biorefining (CUB) as the substitute of unsustainable petrol-based polyols. On this basis, as the primary hydroxyl group providers for the RPFs, the lignin oligomers were isolated from the crude CUB oils that were obtained using the pulping liquors with different n-propanol/H2O ratios. Results demonstrated the CUB lignin oligomers were generally possessed low molecular weight, good miscibility, and high hydroxyl groups content, irrespective of the pulping liquor constituents, affording to highly cross-linked polyurethane networks. Moreover, the CUB pulping liquor's composition and the lignin oligomer substitution rate were proved as two decisive factors to the morphology and mechanical properties of the resulted RPFs. Compared to other groups, the RPF substituted with the lignin oligomers obtained from R7/3 (refer to n-propanol/H2O of 7/3 (v/v) in the pulping liquor) and a polyol substitution rate of 30% exhibited better mechanical properties and a highly assembled nanosized lignin complex. Additionally, the compressive strength and the apparent density of RPFs were highly dependent on the hydroxyl group content in CUB lignin oligomers, while the inner-molecular bonds such as the syringyl/guaiacyl ratios and β-O-4 bonds were also affected to the compressive strength of RPFs. The RPFs prepared by CUB lignin oligomer in the current work provides a foundation for future valorization of the side-streams from lignin-first biorefining processes.

Cold-curing mixtures based on biopolymer lignin complex for casting production in single and small-series conditions

<abstract> <p>This study proves that lignin-based biopolymer materials can be employed as starting materials for the synthesis of novel casting binders that fulfill the current level of characteristics. The optimal concentration of the binder in the mixture was experimentally determined to be 5.8%–6.2%. It has been demonstrated in practice that the employment of ammonium salts as a technical lignosulfonate (TLS) modifier can result in the provision of cold (room temperature) curing of a mixture based on them. It was proposed to use as a technological additive that boosts the strength characteristics of a mixture of substances carboxymethyl cellulose (CMC). In a variety of adhesive materials, it is utilized as an active polymer base. The concentration limits for using CMC in the mixture are set at 0.15%–0.25%. To improve the moldability of the combination, it was suggested that kaolin clay be used as a plasticizing addition. The concentration limits for using a plasticizing additive are set at 3.5%–4.0%. The produced mixture was compared to the analog of the alpha-set method in a comparative analysis. It was discovered that the proposed composition is less expensive, more environmentally friendly, and enables the production of high-quality castings. In terms of physical, mechanical, and technological properties, the created composition of the cold curing mixture is not inferior to analogs from the alpha-set method. For the first time, a biopolymer-based binder system containing technical lignosulfonate with the addition of ammonium sulfate and carboxymethyl cellulose was used in the production of cast iron castings on the case of a cylinder casting weighing 18.3 kg from gray cast iron grade SCh20. Thus, it has been proved possible for the first time to replace phenol-based resin binders with products based on natural polymer combinations. For the first time, a cold-hardening mixture based on technological lignosulfonates has been developed without using hardeners made of very hazardous and cancer-causing hexavalent chromium compounds. But is achieved through a combination of specialized additives, including kaolin clay to ensure the mixture can be manufactured, ammonium sulfate to ensure the mixture cures, and carboxymethyl cellulose to enhance the strength properties of the binder composition. The study's importance stems from the substitution of biopolymer natural materials for costly and environmentally harmful binders based on phenolic resins. This development's execution serves as an illustration of how green technology can be used in the foundry sector. Reducing the amount of resin used in foundry manufacturing and substituting it with biopolymer binders based on technological lignosulfonates results in lower product costs as well as the preservation of the environment. Using lignin products judiciously can reduce environmental harm by using technical lignosulfonates, or compounds based on technical lignin. The combination is concentrated on businesses with single and small-scale manufacturing because it is presumable that this is merely the beginning of the investigation. This study confirms the viability of creating a cold-hardening combination based on technical lignosulfonates in practical applications and supports this with the castings produced, using the creation of a gray cast iron cylinder casting as an example.</p> </abstract>

Fractionation of technical lignin and its application on the lignin/poly-(butylene adipate-co-terephthalate) bio-composites

Complex and heterogeneous structures of lignin impede its further conversion and valorization. Herein, three technical lignins (from softwood, hardwood, and grass) were fractionated with acetone solvent to reduce their structural heterogeneity, which were then blended with poly-(butylene adipate-co-terephthalate) (PBAT) to fabricate biodegradable bio-composites. Macromolecular structures of lignins and their effects on the properties of lignin/PBAT composites were thoroughly investigated. Results showed that all fractionated lignin composites displayed better properties. Particularly, the raw and fractionated softwood lignin-based composites exhibited superior performance compared with others. Benefiting from the lower molecular weight, hydroxyl groups, and condensation, acetone fractionated softwood lignin presented the lowest Tg (115.7 °C), achieving ideal melt miscibility and interfacial interaction between lignin and PBAT. The decreased Tg of lignin facilitated the lignin dispersion in the matrix and increase the mechanical strength of the composites. Overall, the fractionated technical lignin possessed desirable physical and chemical structure features, conferring composites good miscibility and mechanical properties.

Preparation of Fe/N Double Doped Carbon Nanotubes from Lignin in Pennisetum as Oxygen Reduction Reaction Electrocatalysts for Zinc–Air Batteries

Obtaining high value-added products from renewable lignocellulosic biomass is very attractive but still a major challenge. The underutilization of lignin for a high value is considered one of the main obstacles. Herein, we report Fe/N double doped carbon nanotubes with a hollow structure prepared by pyrolysis of an Fe–lignin complex and dicyandiamide. Fe/N double doped carbon nanotubes are expected to replace Pt-based catalysts as efficient, low-cost, and sustainable non-precious metal electrocatalysts for the oxygen reduction reaction in zinc–air batteries. The Fe/N double doped carbon nanotubes as catalysts exhibited good ORR activity with a half-wave potential and onset potential of 0.846 and 0.972 V, respectively, which is comparable to the ORR performance of the state-of-the-art 20% Pt/C catalyst, and the catalyst also has good stability. The primary zinc–air batteries of this catalyst exhibit a high open-circuit voltage, and its good stability ensures that the zinc–air batteries assembled with this catalyst can still maintain high performance during long-term discharge. The enzymatic effect of the cellulosic material obtained by pretreatment in this work is substantially enhanced, and the use of the isolated lignin for the preparation of polyatomically doped catalysts and for zinc–air batteries makes this work demonstrate an integrated biorefinery strategy. This work provides a low-cost and high-efficiency route for the preparation of polyatomically doped carbon nanotubes from lignin, which provides a good direction for the high value-added utilization of lignin.

Nanocellulose Hybrid Lignin Complex Reinforces Cellulose to Form a Strong, Water-Stable Lignin-Cellulose Composite Usable as a Plastic Replacement.

The significant challenges in the use of cellulose as a replacement for plastic are its mechanical properties’ degradation and uncontrolled deformation during the rewetting process. Herein, inspired by the reinforcement of cellulose by lignin in natural plant tissue, a strong and water-stable lignin–cellulose composite (LCC) was developed. A nanocellulose hybrid lignin complex (CHLC) created from bagasse residue after enzymatic hydrolysis was added into a pulp of bleached fibre extracted from pine to produce a lignin–cellulose sheet. The lignin as a water-stable reinforcing matrix, via the hydrogen bonding of the nanocellulose in the CHLC with the fibre was efficiently introduced onto the fibres and the fibre network voids. Compared with a typical lignin-free cellulose sheet, the dry strength and wet strength of the LCC were 218% and 2233% higher, respectively. The developed LCC is an eco-friendly and biodegradable alternative to plastic.

Structure-controlled lignin complex for PLA composites with outstanding antibacterial, fluorescent and photothermal conversion properties

Polylactic acid (PLA) is increasingly being considered as an ideal biodegradable candidate to replace petroleum-based polymers. However, its practical applications are often hampered by the poor mechanical robustness and solo functionality. Herein, based on the mechanical property improvement of PLA we proposed a simple process of assembling lignin-hybridized modifier and PLA matrix, as opposed to the traditional trade-off between mechanical strength and functionality, while anchoring a biofluorescent moiety onto lignin surfaces. Specifically, the fluorophore group could act as interfacial compatibilizer of complex and facilitate the shape-tailored hybrids for promoting functionality flexibility. With the bimetallic hetero-particles, the preferable lignin-assembled complex could be controllably configured as an antibacterial, fluorophore and photothermal agent. Thus, mechanical enhancement, fluorescence introduction and favorable photothermal ability of the resulting PLA composites were successfully achieved for integrated unification of structural robustness, geometric integrity and functional multiplicity, which was never seen in the other reports. The results showed that PLA composites containing 5 wt% modified lignin, 10 wt% zinc oxide, and 5 wt% silver presented excellent mechanical, fluorescent, photothermal conversion properties. By controlling the ZnO content and morphology, strong inhibition of Escherichia coli (Gram-negative) than that of Staphylococcus Aureus (Gram-positive) was also observed. The flake-shaped ZnO /Ag hybrids contributed to better overall performance of PLA composites than the rod-shaped ZnO/Ag. In this work we developed a facile strategy to assemble a bioderived fluorophore with lignin particles for constructing a structure-controlled complex as a multitasking modifier, featuring mechanical unity and functional adaptability. Specifically, the lignin reinforcement and bimetallic hybrids with different morphologies were explored as an effective fluorophore, antibacterial and photothermal agent. Through multiple dehydration reactions, a conjugating fluorophore was successfully grafted on lignin surfaces to serve as an interface modifier without physical changing its structural robustness. And morphology-tailored hybrid was advantageously immobilized on predefined hetero-particle carrier of fluorescent lignin and endowed composites with desirable antimicrobial properties. The developed strategy would expand the functional applications of PLA materials in food packaging, biopharmaceuticals and simple fluorescent anti-counterfeiting.

MANUFACTURE OF LIGNINOLYTIC FUNGI INOCULUM Geotrichum sp. WITH SORGUM (Sorghum bicolor) MEDIA AND ITS EFFECT ON THE QUALITY OF BAMBOO LEAF COMPOST (Bambusa sp.)

Bamboo is a type of plant that grows in Indonesia. So far, people only use the stems and throw away the leaves. As a result, these abundant bamboo leaves become waste. Bamboo leaf waste contains lignin content of 19.8-26.6%, and becomes compost in the long term. The process of composting bamboo leaf litter can be accelerated using an activator such as the inoculum fungi Geotrichum sp. which is ligninolytic so that it can break down lignin complex compounds contained in bamboo leaf waste into simpler compounds. Sorghum contains about 6.5-7.9% fiber. The high fiber content in sorghum seeds can be used as a growth medium for fungal inoculum. The purpose of this study was to determine the effect of sorghum as an inoculum medium for Geotrichum sp. and the effect of inoculum on compost quality. This research was carried out in August - December 2019 at the Microbiology Laboratory of the Biology Department, Faculty of Mathematics and Natural Sciences, Unila. This study used a completely randomized design (CRD) method with 4 treatments, namely Control (Bamboo leaf litter), P1 (Bamboo leaf litter + 1% inoculum), P2 (Bamboo leaf litter + 1.5 % inoculum) and P3 (Bamboo leaf litter). + 2% inoculum) each treatment was repeated 3 times. The variables observed were the number of spores and spore viability using the Colony Forming Unit (CFU) calculation on inoculum and compost. Analysis of the content of C, N, P, and C/N ratio was carried out to determine the quality of the compost. Based on the research results, sorghum can be used as a growth medium for the ligninolytic fungi inoculum Geotrichum sp. with spore viability of 74.18% and the addition of 1.5% inoculum (P2) gave the best results on the quality of bamboo leaf compost (Bambusa sp.)

Advances in lignin valorization from a biorefinery concept

Lignin valorization for fuels and value-added products is essential to enhance the profitability and sustainability of biorefineries. Due to the complex and heterogeneous structure of lignin, technical barriers hinder the implementation of economic lignin utilization. Here, we summarize the major challenges facing lignin valorization processes. Different pretreatment methods, especially emerging combinatorial pretreatment approaches for isolating and tailoring lignin are introduced. To overcome the heterogeneity of lignin structure and improve lignin processability, advances in fractionation approaches including organosolv extraction, membrane technology, and gradient precipitation are analyzed and presented. Furthermore, progress in lignin valorization by thermochemical and biological conversion coupling with pretreatment and fractionation are systematically reviewed. Finally, we discuss advanced strategies and perspectives for future research involving biomass pretreatment, lignin fractionation and conversion processes.

Elucidation of the Structure of Lignin-Carbohydrate Complexes in Ginkgo CW-DHP by 13C-2H Dual Isotope Tracer.

To elucidate the chemical linkages between lignin and carbohydrates in ginkgo cell walls, 13C-2H-enriched cell wall-dehydrogenation polymers (CW-DHP) were selectively prepared with cambial tissue from Ginkgo biloba L. by feeding D-glucose-[6-2H2], coniferin-[α-13C], and phenylalanine ammonia-lyase (PAL) inhibitor. The abundant detection of 13C and 2H confirmed that D-glucose-[6-2H2] and coniferin-[α-13C] were involved in the normal metabolism of ginkgo cambial cells that had been effectively labelled with dual isotopes. In the ginkgo CW-DHP, ketal and ether linkages were formed between the C-α of lignin side chains and carbohydrates, as revealed by solid state CP/MAS 13C-NMR differential spectroscopy. Furthermore, the DMSO/TBAH ionic liquids system was used to fractionate the ball-milled CW-DHP into three lignin-carbohydrate complex (LCC) fractions: glucan–lignin complex (GL), glucomannan–lignin complex (GML), and xylan–lignin complex (XL). The XRD determination indicated that the cellulose type I of the GL was converted into cellulose type II during the separation process. The molecular weight was in the order of Ac-GL > Ac-GML > XL. The 13C-NMR and 1H-NMR differential spectroscopy of 13C-2H-enriched GL fraction indicated that lignin was linked with cellulose C-6 by benzyl ether linkages. It was also found that there were benzyl ether linkages between the lignin side chain C-α and glucomannan C-6 in the 13C-2H-enriched GML fraction. The formation of ketal linkages between the C-α of lignin and xylan was confirmed in the 13C-2H-enriched XL fraction.

Whey protein isolate-lignin complexes as encapsulating agents for enhanced survival during spray drying, storage, and in vitro gastrointestinal passage of Lactobacillus reuteri KUB-AC5

This study aimed to investigate the effect of encapsulant weight ratios of whey protein isolate (WPI)-lignin complex (10:0, 9.5:0.5, 9:1, 8.5:1.5, and 8:2) on survival of Lactobacillus reuteri KUB-AC5 during spray drying, storage, and passage through simulated gastrointestinal tract. Change in the secondary structure of WPI indicated its interaction with lignin. Higher lignin amounts resulted in higher yields and lower moisture contents. After spray drying and 2-month storage, the highest and lowest malondialdehyde contents were found in 10:0 and 9:1 formulations, respectively. After drying, the lowest and highest numbers of viable cells, 8.70 and 9.34 log CFU/g, were found in 10:0 and 9:1 formulations, respectively. After storage at 4 and 37 °C, the lowest and highest survival rates were also observed in these two formulations. At higher lignin concentrations, inactivation rate constants were reduced. After passage through simulated gastrointestinal tract, the highest and lowest cell viability was observed in 9:1 formulation and free cells, respectively. The results showed that microencapsulation using WPI-lignin complexes at 9:1 ratio offered the best protection. Lignin improved survival of spray-dried probiotics through improving the structure and antioxidant properties of WPI.

Enhanced Thermal Stability and Flame Retardancy of Poly(Vinyl Chloride) Based Composites by Magnesium Borate Hydrate-Mechanically Activated Lignin

To improve the thermal stability and flame retardancy of poly(vinyl chloride) (PVC) based composites, magnesium borate hydrate-mechanically activated lignin (MBH-MAL) complex was in-situ synthesized by hydrothermal method for using as a novel additive. In addition, MBH-lignin (MBH-L) complex, MAL, MBH, and common mixing of MBH and MAL (MBH+MAL) were also prepared for comparative investigation. MBH-MAL showed synergistic improving effect on PVC as MBH-MAL/PVC composite exhibited excellent thermal stability and flame retardancy. The static thermal stability time was 871 s and limit oxygen index was 32.54%, indicating that MBH-MAL effectively inhibited the generation of HCl from thermal decomposition of PVC and prevented the combustion of PVC based composites in air. MBH-MAL/PVC composite still exhibited outstanding tensile and flexural properties. Moreover, the enhancing mechanism of MBH-MAL on the thermal stability and flame retardancy of PVC based composites was proposed.

Isolation, screening, and molecular identification of lignin-degrading fungi isolates from Cibinong Science Centre, Indonesia Institute of Sciences, Cibinong, West Java

Lignin is a recalcitrant compound that has potential as fuels and chemicals on industries. Contamination of recalcitrant compound with the lignin-like structure on the ecosystem is being concerned worldwide. Fungi is the most targeted organisms with lignin-degrading ability, can secrets laccase and peroxidase to facilitate free radical chain reaction on lignin complex structure. Isolation, screening and identification for isolate with ligninolytic ability is the main purpose of this project. Phylum Ascomycota and Basidiomycota be the main target of this research. Isolation technics that being used are surface sterilization with distilled water and NaClO on PDA medium. Pure culture with ability to grow on lignin minimal medium with black liquor as the only carbon sources then are identified by molecular identification. Isolates that can grow on lignin minimal medium are identified as Fusarium verticillioides strain CBS 127178, Lasiodiplodia sp. LAS-2016 strain CBS 125262, Trichoderma harzianum strain 35814DRJ, and Lasiodiplodia theobromae strain CBS 127106. Four isolates obtained with lignin-degrading ability then preserved by cryopreservation technic for use in the next projects.

The component composition of planted pine wood cultivated in the boreal zone

Abstract The present study analyzes the composition of pine wood cultivated on artificial plantations in the Leningrad Oblast (Region). Comparing to pine wood from natural stands, a smaller heartwood zone along the height of the pine trunk and a lower content of resinous substances are noted. The content of cellulose and lignin in the heartwood and sapwood of pine is distributed differently along the trunk. The distribution of pentosans and water-soluble substances in the heartwood and sapwood along the trunk is associated with the lignin complex. The component composition of the studied pine wood from planted stands is quite uniform in its indicators if compared to the wood of older natural stands. Sulphate pulping of planted pine wood showed a higher yield of technical cellulose than the average yield from wood obtained at natural stands of the studied region.