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The production of cellulose nanofibers (CNF) usually consist of two different phases. First of all, lignocellulosic fibers need to be treated by means of either chemical, enzymatic or mechanical treatments. Then, in the second phase, the treated lignocellulosic fibers need to be submitted to mechanical fibrillation. This last treatment is usually critical in terms of energy consumption, as well as for providing the appropriate characteristics to the resulting CNF. In the present work, we have investigated the effect of fibrillating lignocellulosic nanofibers (LCNF) made from eucalyptus sawdust by means of high-pressure homogenization and grinding. The obtained results showed that, to achieve the same property level of LCNF, the grinder consumed 12.86 kWh/kg, while the homogenizer, 19.07 kWh/kg, bringing to the light the suitability of grinding for LCNF production. Overall, the present work shows the feasibility of using eucalyptus sawdust, which is a residue from the pulp and paper industry, as raw material for LCNF production, at the same time that brings to the light the relevance of the fibrillation equipment in terms of energy efficiency, approaching the production of LCNF to the industry.

Xylanases can boost pulp bleachability in Elemental Chlorine Free (ECF) processes, but their industrial implementation for producing bleached kraft pulps is not straightforward. It requires enzymes to be active and stable at the extreme conditions of alkalinity and high temperature typical of this industrial process; most commercial enzymes are unable to withstand these conditions. In this work, a novel highly thermo and alkaline-tolerant xylanase from Pseudothermotoga thermarum was overproduced in E. coli and tested as a bleaching booster of hardwood kraft pulps to save chlorine dioxide (ClO2) during ECF bleaching. The extremozyme-stage (EXZ) was carried out at 90 °C and pH 10.5 and optimised at lab scale on an industrial oxygen-delignified eucalyptus pulp, enabling us to save 15% ClO2 to reach the mill brightness, and with no detrimental effect on paper properties. Then, the EXZ-assisted bleaching sequence was validated at pilot scale under industrial conditions, achieving 25% ClO2 savings and reducing the generation of organochlorinated compounds (AOX) by 18%, while maintaining pulp quality and papermaking properties. Technology reproducibility was confirmed with another industrial kraft pulp from a mix of hardwoods. The new enzymatic technology constitutes a realistic step towards environmentally friendly production of kraft pulps through industrial integration of biotechnology., This work was supported by WoodZymes project funded by the Bio-based Industries Joint Undertaking (BBI JU) under GA 792070. The BBI JU received support from the EU’s H2020 research and innovation programme and the Bio Based Industries Consortium.

WOS: 000462022300057 PubMed: 30474775 A newly identified ligninolytic Rhodococcus strain (Rhodococcus sp. T1) was isolated from forestry wastes (Trabzon/Turkey). The DyP type peroxidase of Rhodococcus sp. T1 (DyPT1) was cloned, characterized and paper treated for industrial applications. Molecular weight of the protein was about 38kDa. The kinetic parameters were 0.94mM and 1417.53 mu mol/min/mg for Km and Vmax, respectively. The enzyme was active at the temperature range of 25-65 degrees C and optimum temperature was 35 degrees C, enzyme was stable up to 6 days at room temperature. Optimum pH of the DyPT1 was 4.0 and it was stable between pH 4.0-6.0 up to 8 days at room temperature. Effects of some metal ions, Hemin, and some chemical agents on DyPT1 were determined. Hemin has implemented protective effects on the stability and the activity of the enzyme in long time periods when added into growing medium. DyPT1 was applied to eucalyptus kraft pulp for analyzing the bleaching efficiency, physical and optical tests of the manufuctared paper were carried out. Application of lignin peroxidase to kraft pulp caused a decrease of 5.2 units for kappa number and an increase from 52.05 to 64.18% in the delignification rate. Karadeniz Technical University Research Foundation [FBA-2015-5182] This study was financially supported by Karadeniz Technical University Research Foundation (Project No: FBA-2015-5182).

The bleach plant of a pulp and paper (P&P) mill presents a major source of wastewater containing toxic organic matter characterized as chemical oxygen demand (COD). Due to their high oxidizing power, oxidoreductases hold promise to be a key solution for the removal of dissolved organic material. Here, four oxidoreductases from different enzyme families were selected to treat bleach plant effluents. Haloperoxidase treatment of the final effluent resulted in the highest levels of decolorization (71%) and reduction of aromatic compounds (36%). Using single compound analysis, 27 low molecular weight compounds were found to be persistent throughout the wastewater treatment process and, therefore, classified as hard COD. The tested enzymes efficiently removed several of the identified COD compounds. Hence, this study suggests that the application of oxidoreductases will serve as an environmental-friendly solution for reducing waste from P&P production.

Bioprocessing of pulp requires lignolytic as well as hemicellulolytic enzymes. The present study is the first report of a cocktail of laccase (L), xylanase (X), and mannanase (M), from a single bacterium for pulp biobleaching. A novel strain Bacillus tequilensis LXM 55 produced thermo-alkali stable L + X + M. On optimization higher enzyme yield (IUml−1/fold increase) of laccase (396.35/24.16), xylanase (212.95/81.90) and mannanase (153.33/102.90) were achieved in the cocktail. Treatment of pulp with cocktail of enzymes led to 49.35% reduction in kappa number and considerable enhancement in the brightness (11.59%), whiteness (4.11%), and other pulp properties. Most importantly, no mediator system was required for the application of laccase. 40% less chlorine consumption was required to obtain the paper of the same quality as that of pulp treated without enzyme but with 100% chlorine. Therefore, this cocktail of enzymes is highly suitable for pulp biobleaching in the paper mill.

In order to bleach the eucalyptus kraft pulp, two enzyme treatments involving feruloyl esterase and laccase were used in the TCF sequence. Hydroxycinnamic acids, which were released from lignin subunits by the activity of feruloyl esterase, were used as a natural mediator of laccase. The use of sequentially feruloyl esterase and laccase has much higher pulp bleaching effects than the individual enzymes. GthFAE, BmegLac and GthFAE+BmegLac treatments (X) reduced the kappa number of eucalyptus kraft pulps by indicating 9%, 18%, and 30% delignification rates, respectively. Just like in delignification rates, the highest brightness improvement was achieved from the GthFAE+BmegLac combination. The results of the present study indicated that the natural mediators, which are presented in the structure of lignin, could be used as laccase-mediators for pulp bleaching more efficiently and cost-effectively.

Electron beam irradiation (EBI) is an alternative treatment for intrinsic viscosity (IV) control in cellulose pulps, but has never been integrated in full bleaching sequences for comparison to conventional methods. Both eucalyptus kraft (EK) paper pulp and beech sulfite (BS) dissolving pulp were subjected to totally chlorine free (TCF) bleaching sequences comprising either EBI, ozone, or both for IV control. Additionally, effects of EBI on hexenuronic acid (HexA) and xylan were investigated. IV was adjusted to 450–500 mL g−1 and properties including carbonyl content, kappa, brightness, alkali-resistance and sugar composition were compared. Pulps produced with EBI had a higher alkali-resistance, uniformity and less cellulose oxidation. However, the degree of bleaching (DoB) was low without the use of ozone. HexA content in a birch pulp was halved by EBI. Isolated xylans were more resistant to irradiation than cellulose with little decrease of molar masses and moderate oxidation.

This study aims to understand the effect of micro- and nanofibrillated cellulose (MNFC) on the tensile index, softness, and water absorbency of tissue paper. MNFC was produced from four different fiber sources. The results show that MNFC acts as an effective strength enhancer at the expense of a reduced water absorbency and softness. The impact of the fiber source on MNFC manufacturing cost and the trade-off with performance was also investigated. MNFCs produced from southern bleached hardwood kraft, northern bleached softwood kraft, and deinked pulp exhibited similar performance trends with the MNFC from the deinked pulp having a significantly lower cost. This suggests that MNFCs with similar degrees of fibrillation may be used interchangeably regardless of the fiber source, revealing the possibility to minimize MNFC manufacturing costs based on fiber selection. MNFC produced from bleached Eucalyptus kraft showed the lowest degree of fibrillation and the lowest strength improvements among the MNFCs evaluated.

The aim of this work was to study the impact of shortening kraft pulping (KP) process integrated with extended oxygen delignification (OD) on the biorefinery process performance of eucalyptus. Data showed that using kraft pulps with high kappa number could improve the delignification efficiency of OD, reduce hexenuronic acid formation in kraft pulps. Pulp viscosity for a target kappa number of ∼10 was comparable to that obtained from conventional KP and OD process. The energy and alkali consumption in the integrated biorefinery process could be optimized when using a KP pulp with kappa number of ∼27. The process could minimize the overall methanol formation, but greater amounts of carbonate and oxalate were formed. The information from this study will be helpful to the future implementation of short-time KP integrated with extended OD process in actual pulp mill applications for biorefinery, aiming at further improvement in the biorefinery effectiveness of hardwood.

Pulp and paper mill effluents (PPMEs) have been shown to increase gonad size, cause early maturation, and disrupt hormone functions in native and non-native Chilean fish. In this study, we assessed reproductive (plasma vitellogenin; VTG, gonad development) and metabolic (ethoxyresorufin-. O-deethylase activity; EROD) end points, relative liver size (LSI) and condition factor (K) of juvenile female and male rainbow trout exposed to effluents. Unlike previous studies, which have focus either on the specific effects of effluent on fish in laboratory exposures or biotic population statuses downstream of discharge sites, we simultaneously assessed the impacts of PPMES on trout using two approaches: (1) laboratory exposures of tertiary treated PPME produced from processing Eucalyptus globulus or Pinus radiata; and (2) in situ bioassay downstream of the combined discharge of the same pulp mill. Despite an increase in the average gonadosomatic index (GSI) in exposed fish, no statistical differences in gonad size between exposed and unexposed individuals was detected. However, both female and male fish exposed to effluents showed significantly higher concentrations of plasma VTG, so more in fish exposed to Eucalyptus-based effluent when compared to Pinus PPME. In addition, male fish showed intersex characteristics in all exposure assays (Eucaliptus and Pinus) and, despite the low concentration of effluent in the river (

O objetivo deste estudo foi avaliar as propriedades de polpas kraft marrons de madeiras de Eucalyptus grandis e Eucalyptus urograndis de composição química distinta, principalmente em relação aos seus conteúdos de xilanas, para fabricação de papéis. As polpas marrons de número kappa 17-18 e conteúdos de xilanas variando de 6 a 21% foram produzidas sob diferentes protocolos de cozimento: 1) kraft convencional; 2) pré-hidrólise kraft; 3) kraft de alta alcalinidade; e 4) kraft de alto rendimento. As polpas marrons foram refinadas em moinho PFI e seus respectivos papéis produzidos foram avaliados quanto às suas propriedades físico-mecânicas e ópticas. De modo geral, as propriedades de resistência dos papéis foram beneficiadas pelo conteúdo de xilanas. Para níveis muito altos de refino, ocorreram quedas bruscas de resistência ao rasgo para os papéis e o consumo de energia de refino foi influenciado pelo conteúdo de xilanas nas polpas marrons. Os mais altos valores de volume específico aparente foram obtidos para os papéis com baixo conteúdo de xilanas, o que os torna interessantes, se branqueados, no segmento de papéis tissue. Os papéis com elevado conteúdo de xilanas apresentaram-se economicamente atrativos e com características de resistências adequadas para o segmento de papéis de imprimir e escrever. The objective of this study was to evaluate properties of brown pulp from Eucalyptus grandis and Eucalyptus urograndis of distinct chemical composition, mainly in refers to its xylans content, for the manufacture of tissue and printing and writing (P&W) paper grades. Brow pulps of kappa number 17-18 and xylans contents varying 6-21% had been produced under different cooking protocols: 1) conventional kraft; 2) pre-hydrolysis kraft; 3) high alkalinity kraft; and 4) kraft of high yield. The brown pulps had been beated in PFI mill and its respective produced papers had been evaluated as regards physical-mechanical and optic properties. The highest bulk values had been gotten for papers with low xylans contents, what had revealed interesting, if bleached, in the manufacture of tissue papers. The papers with high xylans contents, had been presented technically viable and with resistance characteristics adjusted for the manufacture of P&W papers.

The effectiveness of a biorefinery based on an HWE–Kraft–ECF bleaching process and the end use of pulp was systematically evaluated. Using a P-factor of 198, nearly 30% of xylan-based sugars were recovered. The resulting pulp and paper properties were found to be comparable with the control. A maximum xylan-based sugar recovery of nearly 50% was achieved at a P-factor of 738. Although the strength of this P-factor induced handsheet was lower than that of the control by about 20%, the corresponding pulp was sufficient for dissolving pulp application. However, once the P-factor rose above 1189, hemicellulose sugars were significantly degraded into furans; pulp and paper properties were also deteriorated due to cellulose degradation, lignin deposition and condensation. Thus, considering the different end use of pulps, the performance of an HWE-based biorefinery could be balanced by its HWE severity.

The main objective of this study was to analyse cost reduction by reducing the use of fresh water in the cellulose bleaching process and to make it easier to obtain water in a closed circuit. Eucalyptus oxygen delignified industrial pulp was used. The pulp was bleached 10 times in the D(E+P)DP sequence in the same conditions. Counter current washing was used in the bleaching stages, and each sequence was carried out with different wash factors: 9, 6, 3, and 0 m³ of distilled water/ton of oven dry pulp. The goal was to reach brightness of 92±0.5% ISO. The results showed that there was a chemical oxygen demand (COD) increase and brightness reversion, but the kappa number and viscosity did not change. The apparent colour was increased by increasing COD in the effluent during the cycles and by decreasing the wash water. Up to 3 m³/t of water was tolerable and even recommended to wash pulp. Nine cubic metre per tonne of fresh water is most commonly used in the industry, so water savings make the implementation of the process possible.