Sources and transformations of dissolved lignin phenols and chromophoric dissolved organic matter in Otsuchi Bay, Japan

Dissolved lignin phenols and optical properties of dissolved organic matter (DOM) were measured to investigate the sources and transformations of terrigenous DOM (tDOM) in Otsuchi Bay, Japan. Three rivers discharge into the bay, and relatively high values of syringyl:vanillyl phenols (0.73 ± 0.07) and cinnamyl:vanillyl phenols (0.33 ± 0.10) indicated large contributions of non-woody angiosperm tissues to lignin and tDOM. The physical mixing of river and seawater played an important role in controlling the concentrations and distributions of lignin phenols and chromophoric DOM (CDOM) optical properties in the bay. Lignin phenol concentrations and the CDOM absorption coefficient at 350 nm, a(350), were strongly correlated in river and bay waters. Measurements of lignin phenols and CDOM in bay waters indicated a variety of photochemical and biological transformations of tDOM, including oxidation reactions, photobleaching and a decrease in molecular weight. Photodegradation and biodegradation of lignin and CDOM were investigated in decomposition experiments with river water and native microbial assemblages exposed to natural sunlight or kept in the dark. There was a rapid and substantial removal of lignin phenols and CDOM during the first few days in the light treatment, indicating transformations of tDOM and CDOM can occur soon after discharge of buoyant river water into the bay. The removal of lignin phenols was slightly greater in the dark (34%) than in the light (30%) during the remaining 59 days of the incubation. Comparison of the light and dark treatments indicated biodegradation was responsible for 67% of total lignin phenols removal during the 62-day incubation exposed to natural sunlight, indicating biodegradation is a dominant removal process in Otsuchi Bay.Ministry of Education, Culture, Sports, Science, and Technology; 1504137 - National Science Foundatio

Anaerobic co-digestion of acetate-rich with lignin-rich wastewater and the effect of hydrotalcite addition

The methane potential and biodegradability of different ratios of acetate and lignin-rich effluents from a neutral sulfite semi-chemical (NSSC) pulp mill were investigated. Results showed ultimate methane yields up to 333 ± 5 mL CH4/gCOD when only acetate-rich substrate was added and subsequently lower methane potentials of 192 ± 4 mL CH4/gCOD when the lignin fraction was increased. The presence of lignin showed a linear decay in methane production, resulting in a 41% decrease in methane when the lignin-rich feed had a 30% increase. A negative linear correlation between lignin content and biodegradability was also observed. Furthermore, the effect of hydrotalcite (HT) addition was evaluated and showed increase in methane potential of up to 8%, a faster production rate and higher soluble lignin removal (7–12% higher). Chemical oxygen demand (COD) removal efficiencies between 64 and 83% were obtained for all samples.Peer ReviewedPostprint (author's final draft

Synthesis, Characterization, and Utilization of a Lignin-Based Adsorbent for Effective Removal of Azo Dye from Aqueous Solution

How to effectively remove toxic dyes from the industrial wastewater using a green low-cost lignocellulose-based adsorbent, such as lignin, has become a topic of great interest but remains quite challenging. In this study, cosolvent-enhanced lignocellulosic fractionation (CELF) pretreatment and Mannich reaction were combined to generate an aminated CELF lignin which is subsequently applied for removal of methylene blue and direct blue (DB) 1 dye from aqueous solution. 31P NMR was used to track the degree of amination, and an orthogonal design was applied to determine the relationship between the extent of amination and reaction parameters. The physicochemical, morphological, and thermal properties of the aminated CELF lignin were characterized to confirm the successful grafting of diethylenetriamine onto the lignin. The aminated CELF lignin proved to be an effective azo dye-adsorbent, demonstrating considerably enhanced dye decolorization, especially toward DB 1 dye (>90%). It had a maximum adsorption capacity of DB 1 dye of 502.7 mg/g, and the kinetic study suggested the adsorption process conformed to a pseudo-second-order kinetic model. The isotherm results also showed that the modified lignin-based adsorbent exhibited monolayer adsorption. The adsorbent properties were mainly attributed to the incorporated amine functionalities as well as the increased specific surface area of the aminated CELF lignin

Lignin removal from Aqueous Solution using Calcium Lactate: the effect of Polymers and Magnesium Hydroxide as a Flocculant aids

Palm oil mill effluent (POME) which is mainly associated with lignin has becoming a major concern due to its highly coloured appearance. The main colourant, i.e. lignin particles are difficult to be degraded in oil palm conventional biological ponding system. Coagulation/flocculation could remove the lignin prior to biological treatment and is considered vital to minimize the recalcitrance nature of palm oil mill effluent particles. In this study, the coagulation/flocculation process was investigated to remove lignin particles from aqueous solution. A non-toxic and biodegradable chemical i.e. calcium lactate was utilized as a destabilizer for the removal of lignin with an addition of several flocculants aid i.e. anionic polyacrylamide (APAM), polydimethyldiallylammonium chloride (polyDADMAC) and magnesium hydroxide. The effect of coagulant and flocculant aids dosage was investigated. From this study, it was found that the optimum condition was at 0.7g/L of calcium lactate and 0.5-1.0mg/L of APAM with ~64% of lignin removal. At concentration of 4 mg/L, the removal of lignin for APAM and polyDADMAC is similar. This result shows that the calcium lactate has potential as a coagulant and the efficiency can be enhanced with an addition of polymeric flocculant aids

Biomass Derived Lignin Polymer Modification for Sustainable Chemical Engineering Applications

Lignin is an abundant naturally occurring plant-based polymer that is branched, highly unsaturated, and rich in aliphatic and aromatic hydroxyl groups. Lignin is a significant byproduct of the wood pulp and paper industries; however, it has yet to be widely utilized in commercial applications due to its non-linear structure, broad range of molecular weights, hydrophobicity, high rigidity, and brittleness. Recent investigations into modifying lignin to broaden its potential uses have shown promising results. This thesis explores different modification techniques of the naturally occurring hardwood lignin polymer for specific applications in areas of water treatment and polyurethane (PU) production. The first project utilized lignin phenolation and subsequent amination for the removal of toxic anionic azo dyes from solution. Each reaction step characterized by Fourier transform infrared (FTIR) spectroscopy to confirm chemical reaction, and ultraviolet-visible light spectroscopy (UV-vis) to monitor dye removal over time throughout multiple dye removal tests. The second project aimed to modify lignin to act as the foundational polyol and isocyanate precursors of PU synthesis, for ultimate use in a completely lignin-based PU product. Building upon the successful results in the synthesis of two modified lignin-based polyols, these polyols were employed to develop three partially lignin-based PUs. Each of the lignin-based PU products were characterized by FTIR spectroscopy, and both water contact angle goniometry and thermogravimetric analysis (TGA) to assess wettability and thermal stability of the final PU products respectively

Biomass Derived Lignin Polymer Modification for Sustainable Chemical Engineering Applications

Lignin is an abundant naturally occurring plant-based polymer that is branched, highly unsaturated, and rich in aliphatic and aromatic hydroxyl groups. Lignin is a significant byproduct of the wood pulp and paper industries; however, it has yet to be widely utilized in commercial applications due to its non-linear structure, broad range of molecular weights, hydrophobicity, high rigidity, and brittleness. Recent investigations into modifying lignin to broaden its potential uses have shown promising results. This thesis explores different modification techniques of the naturally occurring hardwood lignin polymer for specific applications in areas of water treatment and polyurethane (PU) production. The first project utilized lignin phenolation and subsequent amination for the removal of toxic anionic azo dyes from solution. Each reaction step characterized by Fourier transform infrared (FTIR) spectroscopy to confirm chemical reaction, and ultraviolet-visible light spectroscopy (UV-vis) to monitor dye removal over time throughout multiple dye removal tests. The second project aimed to modify lignin to act as the foundational polyol and isocyanate precursors of PU synthesis, for ultimate use in a completely lignin-based PU product. Building upon the successful results in the synthesis of two modified lignin-based polyols, these polyols were employed to develop three partially lignin-based PUs. Each of the lignin-based PU products were characterized by FTIR spectroscopy, and both water contact angle goniometry and thermogravimetric analysis (TGA) to assess wettability and thermal stability of the final PU products respectively

Optimisation of alkali treatment of banana fibres on lignin removal

Alkali treatment of banana fibres has been used for lignin removal. The effects of various experimental parameters, such as alkali concentration, time and temperature, on lignin removal of banana fibres have been ascertained by response surface methodology using Box-Behnken design. The optimum conditions for lignin decomposition are identified as alkali concentration 11g/L, treatment time 150 min and temperature 90 ºC. The fibres treated under the optimum conditions are characterized based on chemical composition, diameter, density, moisture regain, strength, crystallinity and colour

Experimental investigation on surface characterization of chemical treated Natural fiber composite

In this research work removal of lignin and hemicelluloses for untreated coir fiber reinforced composites was accomplished by suitable chemical treatment namely new method at optimum fiber loading such as 25% and 30%. To avoid the problem of untreated coir fiber, chemical treatment was done. Final treated fiber extraction process was gone through new method. It results in treated cellulose composite at 25% and 30% lignin and hemicelluloses was found to be decreased was revealed in Fourier transform infrared spectroscopy analysis, it shows defibrillation, de-polymerization in treated composite was revealed in scanning electron microscopy analysis, and shows high oxygen content percentage than carbon content percentage about 22.06% which demonstrates removal of lignin in treated composite, was revealed in element detection analysis.. The main objective was accomplished by the removal of lignin and hemicelluloses of natural fiber through suitable chemical treatment and at optimum fiber loadin

The development and optimisation of a lab-scale process for biological treatment of lignin-rich wastewater using biofilms formed by Nuerospora Discreta

Lignin is a complex biopolymer found in lignocellulosic materials used as raw material in pulp and paper making. Lignin is processed as a by-product of low value and is discarded in the wastewater. This wastewater is highly polluting due to dissolved lignin degradation products, which give it an intense colour and high chemical oxygen demand (COD), causing harm to aquatic life, plants, and animals. Removal or degradation of lignin has been shown to improve water quality in industrial wastewater, however, the complex structure of lignin makes it difficult to be degraded. Advancements in wastewater treatment methods, such as the conventional physiochemical and thermochemical methods employed, have a detrimental impact on the environment due to the production of hazardous by-products and high energy requirements. Biological treatment of lignin using fungi has the potential to overcome many of these roadblocks and lead to a successful process. This thesis aims to develop a single-step biological process for treating wastewater from the kraft process used in paper-making. Neurospora discreta, an ascomycete fungus, has been reported to degrade lignin effectively in lignocellulosic biomass, as it possesses the ligninolytic enzymatic machinery required for lignin degradation. It also has a unique ability to form robust biofilms at the air and liquid interface. In this research, N. discreta was evaluated for its ability to treat lignin-rich wastewater for the first time. The process optimisation was initially developed on synthetic wastewater using alkali lignin, followed by studies using wastewater provided by a pulp and paper-producing company. Firstly, the Taguchi statistical design of experiments, was used to identify the critical process levers for enhancing lignin degradation. Secondly, the addition of naturally formed lignin degradation intermediates in the fungal-treated wastewater spent media was evaluated as a strategy to increase lignin and COD removal. Finally, the biofilms were tested in a continuous repeated batch process, where actively metabolising mature biofilms were transferred to fresh wastewater in repeated cycles. The process was then scaled-up eightfold to tray reactors. This research has developed a fungal biofilm-based sustainable, eco-friendly and scalable alternative for lignin and COD removal in industrial wastewater. The fungal biofilm treatment proved to be efficient in removing 67.8% of standard kraft lignin in synthetic wastewater. The process efficiencies, while treating real wastewater from pulp and paper mill, were improved significantly by using lignin degradation intermediates as additives. The lignin and COD removal efficiencies of 70% were noted in cultures fed with lignin degradation intermediates compared to 57% and 50% respectively, in unfed culture. Enzyme activity for polyphenol oxidase (PPO), versatile peroxidase (VPO) and laccase were also seen where VPO was reported for the first time in a Neurospora species. The repeated-batch treatment process was evaluated and resulted in an efficient scalable process

Laccase-Mediator Pretreatment of Wheat Straw Degrades Lignin and Improves Saccharification

14 páginas.-- 4 figuras.-- 4 tablas.-- 49 referenciasThe authors thank Dr. Angulo for performing the NMR analyses that were acquired on a Bruker AVANCE III 500-MHz instrument from the NMR facilities of the General Research Services of the University of Seville (SGI CITIUS)gricultural by-products such as wheat straw are attractive feedstocks for the production of second-generation bioethanol due to their high abundance. However, the presence of lignin in these lignocellulosic materials hinders the enzymatic hydrolysis of cellulose. The purposes of this work are to study the ability of a laccase-mediator system to remove lignin improving saccharification, as a pretreatment of wheat straw, and to analyze the chemical modifications produced in the remaining lignin moiety. Up to 48 % lignin removal from ground wheat straw was attained by pretreatment with Pycnoporus cinnabarinus laccase and 1-hydroxybenzotriazole (HBT) as mediator, followed by alkaline peroxide extraction. The lignin removal directly correlated with increases (∼60 %) in glucose yields after enzymatic saccharification. The pretreatment using laccase alone (without mediator) removed up to 18 % of lignin from wheat straw. Substantial lignin removal (37 %) was also produced when the enzyme-mediator pretreatment was not combined with the alkaline peroxide extraction. Two-dimensional nuclear magnetic resonance (2D NMR) analysis of the whole pretreated wheat straw material swollen in dimethylsulfoxide-d6 revealed modifications of the lignin polymer, including the lower number of aliphatic side chains involved in main β-O-4′ and β-5′ inter-unit linkages per aromatic lignin unit. Simultaneously, the removal of p-hydroxyphenyl, guaiacyl, and syringyl lignin units and of p-coumaric and ferulic acids, as well as a moderate decrease of tricin units, was observed without a substantial change in the wood polysaccharide signals. Especially noteworthy was the formation of Cα-oxidized lignin units during the enzymatic treatment.This study was funded by the INDOX EU-project (KBBE-2013-7-613549); the LIGNOCELL, LIGNIN, NOESIS, and BIORENZYMERY Spanish MICINN (co-financed by FEDER funds) projects (AGL2011-25379, CTQ2014-60764-JIN, BIO2014-56388 R and AGL2014-53730-R); and the CSIC (201440E097) Project. A.P. thanks the Spanish MINECO for a FPI fellowship. A. Lomascolo and E. Record from INRA (Marseille, France) are acknowledged for the P. cinnabarinus laccase, and H. Lund and M. Tovborg from Novozymes (Bagsvaerd, Denmark) for Celluclast 1.5L and Novozyme 188.Peer reviewe