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This paper reports an innovative study that aims to address key issues in the efficient recycling of wastepaper cellulose. The research team utilized the temperature-responsive upper critical solution temperature (UCST) polymer P(NAGA-b-DMA) in combination with the LytA label's affinity for choline analogs. This innovative approach enabled them to successfully develop a novel soluble immobilized enzyme, P(NAGA-b-DMA)-cellulase. This new enzyme has proven highly effective, significantly enhancing the degradation of wastepaper cellulose while demonstrating exceptional stability. Compared with the traditional insoluble immobilized cellulase, the enzyme showed a significant improvement in the pH, temperature stability, recycling ability, and storage stability. A kinetic parameter calculation showed that the enzymatic effectiveness of the soluble immobilized enzyme was much better than that of the traditional insoluble immobilized cellulase. After the immobilization reaction, the Michaelis constant of the immobilized enzyme was only increased by 11.5%. In the actual wastepaper degradation experiment, the immobilized enzyme was effectively used, and it was found that the degradation efficiency of wastepaper cellulose reached 80% of that observed in laboratory conditions. This novel, thermosensitive soluble immobilized cellulase can efficiently catalyze the conversion of wastepaper cellulose into glucose under suitable conditions, so as to further ferment into environmentally friendly biofuel ethanol, which provides a solution to solve the shortage of raw materials and environmental protection problems in the paper products industry. [ABSTRACT FROM AUTHOR]

The demand for high-performance bio-based materials towards achieving more sustainable manufacturing and circular economy models is growing significantly. Kraft lignin (KL) is an abundant and highly functional aromatic/phenolic biopolymer, being the main side product of the pulp and paper industry, as well as of the more recent 2nd generation biorefineries. In this study, KL was incorporated into a glassy epoxy system based on the diglycidyl ether of bisphenol A (DGEBA) and an amine curing agent (Jeffamine D-230), being utilized as partial replacement of the curing agent and the DGEBA prepolymer or as a reactive additive. A D-230 replacement by pristine (unmodified) KL of up to 14 wt.% was achieved while KL–epoxy composites with up to 30 wt.% KL exhibited similar thermo-mechanical properties and substantially enhanced antioxidant properties compared to the neat epoxy polymer. Additionally, the effect of the KL particle size was investigated. Ball-milled kraft lignin (BMKL, 10 μm) and nano-lignin (NLH, 220 nm) were, respectively, obtained after ball milling and ultrasonication and were studied as additives in the same epoxy system. Significantly improved dispersion and thermo-mechanical properties were obtained, mainly with nano-lignin, which exhibited fully transparent lignin–epoxy composites with higher tensile strength, storage modulus and glass transition temperature, even at 30 wt.% loadings. Lastly, KL lignin was glycidylized (GKL) and utilized as a bio-based epoxy prepolymer, achieving up to 38 wt.% replacement of fossil-based DGEBA. The GKL composites exhibited improved thermo-mechanical properties and transparency. All lignins were extensively characterized using NMR, TGA, GPC, and DLS techniques to correlate and justify the epoxy polymer characterization results. [ABSTRACT FROM AUTHOR]

Eucalyptus sawdust is a forest residue that, through a biorefinery approach, can be used to manufacture value-added products in the pulp and paper industries as well as to produce a biofuel. This study examines the suitability of a sequential thermochemical pretreatment that uses processes and reagents commonly utilized in the pulp and paper industry to separate valuable biomass components from eucalyptus sawdust and increase its enzymatic digestibility for ethanol production. The research strategy was based on a forest biorefinery that can be integrated into an existing industrial plant for the production of cellulose pulp. A combination of alkaline solutions was evaluated to obtain an extract rich in tannins and intended to be used in the formulation of wood adhesives. A second alkaline treatment was used to recover lignin and hemicellulose components and improve cellulose digestibility. The cellulose fraction was fermented using three commercial Saccharomyces cerevisiae yeasts (Thermosacc®, PE-2, and CAT). Different process configurations (separate hydrolysis and fermentation (SHF), pre-saccharification followed by simultaneous saccharification and fermentation (PSSF), and simultaneous saccharification and fermentation (SSF)) at 16% (w/v) solid loading by Thermosacc® yeast were also studied. Thermosacc® yeast enabled higher ethanol production than the other strains but resulted in similar productivity. The two-stage alkaline pretreatment of eucalyptus sawdust was successful in recovering 34 g of tannins, 56 g of xylo-saccharides, 16 g of acetic acid, and 90 g of lignin and produced 152 g of ethanol from 1 kg of dry eucalyptus sawdust. [ABSTRACT FROM AUTHOR]

Congestion is a well-known economic phenomenon in which excessive inputs lead to a decrease in the maximum possible outputs. This study analyzes the relationship between congestion and overinvestment using a data envelopment analysis framework to reveal that some congestion can be eliminated by increasing inputs. The proposed approach classifies congestion into two categories, relative and absolute congestion, depending on the possibility of eliminating congestion by increasing inputs. Corresponding methods for identifying and measuring congestion are proposed and employed for empirical analyses examining China's papermaking and paper products industry. We find that most congestion in 2013–2016 is in the relative congestion and could be eliminated by increasing inputs. The primary causes of congestion are identified based on our analysis and corresponding policy suggestions are proposed for eliminating congestion. [ABSTRACT FROM AUTHOR]

Pulp feedstock components (including extractives, lignin and holocellulose) are major products of the pulp and paper industry, and their proportion in production feedstock (e.g., wood) greatly impact pulp yield and pulp production costs. Near-infrared (NIR) spectroscopy offers a potential solution for rapid characterizing physical and chemical properties of woody biomass. However, NIR models are highly specific to the physical form and species of the samples used in the production process. Traditional calibration transfer (CT) methods usually fail to adapt NIR models to significant differences between spectra. Adversarial transfer learning (ATL) strategies, an emerging algorithm in computer imaging, align source and target distributions by introducing adversarial mechanisms. For the first time, deep ATL architecture, coupled with NIR spectroscopy (collected from ASD LabSpecPro spectrometer), was applied to quantitatively predict the pulpwood feedstock component content for adapting models of different physical forms (wood blocks, wood meals) and tree species to each other without the need for constructing a new model. It was discovered that ATL methods, including domain adversarial neural networks (DANN), domain separation networks (DSN), and dynamic adversarial adaptation networks (DAAN) not only remove the differences between wood block and wood meal spectral data sources (i.e., domains), but also make desired predictions for cross-species domain adaptation. The robustness and stability of the transferred models exceed those of traditional CT and transfer learning methods. Our results suggest that ATL models could be effectively adapted to polymorphic, multi-species pulp feedstock data, and can be extended to the detection and inversion of other feedstock properties. [ABSTRACT FROM AUTHOR]

In this study, lignin was chemically modified to promote hydrogel degradation as a source of carbon and nitrogen for a bacterial consortium consisting of P. putida F1, B. cereus and, B. paramycoides. A hydrogel was synthesized using acrylic acid (AA), acrylamide (AM), and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and cross-linked with the modified lignin. The structural changes and mass loss in the hydrogel, as well as its final composition, were evaluated as functions of the growth of the selected strains in a culture broth with the powdered hydrogel. The average loss was 18.4% wt. The hydrogel was characterized using FTIR spectroscopy, scanning electronic microscopy (SEM), elemental analysis (EA), and thermogravimetric analysis (TGA) before and after bacterial treatment. FTIR showed that the carboxylic groups present in both the lignin and the acrylic acid of the hydrogel decreased during bacterial growth. The bacteria showed a preference for the biomaterial components of the hydrogel. SEM demonstrated superficial morphological changes in the hydrogel. The results reveal that the hydrogel was assimilated by the bacterial consortium while preserving the water retention capacity of the material and that the microorganisms carried out a partial biodegradation of the hydrogel. The results of the EA and TGA confirm that the bacterial consortium not only degraded the biopolymer (lignin), but also used the synthetic hydrogel as a carbon source to degrade its polymeric chains and modified original properties. This modification with lignin as a crosslinker (which is a waste product of the paper industry) is therefore proposed to promote hydrogel degradation. [ABSTRACT FROM AUTHOR]

Sulfite and kraft pulping are two principal methods of industrial delignification of wood. In recent decades, those have been considered as possibilities to pretreat recalcitrant wood lignocellulosics for the enzymatic hydrolysis of polysaccharides and the subsequent fermentation of obtained sugars to valuable bioproducts. Current work compares chemistry and technological features of two different cooking processes in the preparation of polysaccharide substrates for deep saccharification with P. verruculosum glycosyl hydrolases. Bleached kraft and sulfite pulps were subjected to hydrolysis with enzyme mixture of high xylanase, cellobiohydrolase, and β-glucosidase activities at a dosage of 10 FPU/g of dry pulp and fiber concentration of 2.5, 5, and 10%. HPLC was used to analyze soluble sugars after hydrolysis and additional acid inversion of oligomers to monosaccharides. Kraft pulp demonstrated higher pulp conversion after 48 h (74–99%), which mostly resulted from deep xylan hydrolysis. Sulfite-pulp hydrolysates, obtained in similar conditions due to higher hexose concentration (more than 50 g/L), had higher fermentability for industrial strains producing alcohols, microbial protein, or organic acids. Along with saccharification, enzymatic modification of non-hydrolyzed residues occurred, which led to decreased degree of polymerization and composition changes in two industrial pulps. As a result, crystallinity of kraft pulp increased by 1.3%, which opens possibilities for obtaining new types of cellulosic products in the pulp and paper industry. The high adaptability and controllability of enzymatic and fermentation processes creates prospects for the modernization of existing factories. [ABSTRACT FROM AUTHOR]

Lignin is a waste product in the paper industry and lignocellulosic biorefineries, in addition to being the second most abundant renewable biopolymer on Earth. Valorization of useless lignin into high value‐added advanced materials not only helps address the environmentally detrimental biowaste but also satisfies the societal need for energy. While lignin has been converted into porous carbon, made into slurry, and pasted onto metal forms as an electrode for lithium‐ion batteries and supercapacitors, there remains issues with how to scale up the process while achieving great area and mass capacitances in the fabricated lignin‐carbon electrodes. In this work, a thick freestanding electrode coupled by lignin carbon and sodium without any binder and additives was fabricated demonstrating a specific area capacitance of 19.7 F cm−2 at a current density of 1 mA cm−2, which is the highest among to date reported freestanding lignin carbon electrodes with similar thickness. This excellent electrochemical performance originates from high electro‐positivity and oxygen content promoted by the sodium. This work brings a new strategy towards lignin utilization and energy storage through coupling lignin carbon and alkali metals. [ABSTRACT FROM AUTHOR]