POLYPYRROLE SYNTHESIS VIA CARBOXYMETHYLCELLULOSE-IRON COMPLEXES

Polypyrrole (PPy) was chemically synthesised at two pH levels (pH = 2 and unadjusted pH, i.e. 6.6) using pre-formed carboxymethylcellulose-iron (CMC-Fe) complexes. The CMC-Fe complexes were prepared at a fixed CMC concentration, i.e. 5.5x10-5 mol/L, and with an increasing FeCl3 amount (from 4x10-3 to 5x10-2 mol/L). The quantity of iron bound to CMC was determined by the inductively coupled plasma (ICP-MS) method. In order to understand the interactions between CMC and iron, speciation of the systems was simulated by Phreeqc software. SEM analysis showed that, in some conditions (particularly at pH = 2), Py polymerised within the CMC-Fe complexes, forming particles with size ranging between 300 and 600 nm. In order to evaluate polymer electric conductivity, films were prepared by direct casting of the PPy-CMC-Fe dispersions with and without addition of film-forming CMC, and bulky PPy-CMC-Fe pellets were obtained by compression. Despite the different arrangement PPy-CMC-Fe particles in dry films, the amount of iron bound to CMC during the formation of CMC-Fe complexes was found to be the dominant parameter affecting polymer conductivity

THE IMPACT OF STORAGE CONDITIONS ON THE FOREST BIOMASS QUALITY FOR BIOFUELS PRODUCTION

Biomass quality is an essential parameter for the production of biofuels both by thermal ways (gasification, pyrolysis, torrefaction, etc) or biochemical ways (enzymatic hydrolysis and yeast saccharification). Storage is one of the most important parameters to be taken in account in the logistics chains of biomass supply for biofuel conversion sites. Morever, some benefits in terms of biomass quality can be obtained by storing biomass prior transportation or usage. In this case, storage can be considered as a pre-treatment of biomass for biofuel production. In this project, we have studied the evolution of biomass quality of different wooden resources (softwoods and hardwoods; short/very-short rotation coppices and residues of forest exploitation) stored under different conditions : seasons (spring/summer or autumn/winter), sites (forest roadside and storage platforms; uncovered and covered; under water sprinkling). Two locations were also tested, one in Bordeaux area (southwest of France) and the second in Dijon area (northeast of France). Different piles of approximately 10 m3 (2.5 to 3.5 tons of wood chips) were constituted for each modality. Samples were taken from two different levels of the piles at different intervals of storage (0 to 6 months). The following biomass quality parameters were followed : moisture content, elemental (C, H, O, N, S, Cl) and chemical (extractives, lignin, polysaccharides – cellulose and hemicelluloses, C5 and C6 sugars contents) composition; heating value; ash content, fusibility behaviour and composition. The results obtained indicated that the conditions of storage strongly influence the biomass quality, especially for the thermal conversion. The type of initial raw material (softwoods or hardwoods / short/very-short rotation coppices and residues of forest exploitation) are also of major importance, especially if the biomass material is stored with or without leaves. In that way, the season aspect becomes very important. Water sprinkling is an interesting way to remove certain compounds, such ash constituents or extractives, partially responsible for tar formation. On the other way, in this case a compulsory drying step is needed and a careful energy balance is needed in order to evaluate the pertinence or not of this technology. Concerning the biochemical conversion, no major differences were observed for the mono/polysaccharides contents. However, the removal of certain elements/substances could impact the enzymatic hydrolysis and fermentation for bioethanol production

POLYPYRROLE AND POLYPYRROLE/WOOD-DERIVED MATERIALS CONDUCTING COMPOSITES: A REVIEW

Wood and cellulose derivatives, in both fibrous and water-soluble macromolecular form, are emerging as outstanding candidates for organic electronics applications due to their large-scale availability, low cost, and easy processability. Paper and wood fibre-based derivatives are considered to be materials of choice as supports for communication world-wide. The interest in producing inexpensive and universally available conducting polymer/cellulose fibres substrates resides in the possibility of creating new materials that can be used for a broad range of advanced applications. For instance, PPy/cellulose fibres composites can be used for the preparation of energy storage devices thanks to the conjugation of the high specific area of cellulose fibres and the electrochemical properties of PPy. Other possible applications of such composites are in the area of the antistatic materials, sensors, electromagnetic interference shielding materials, smart packaging, and tissues. Concerning the woody polymers, some of them (i.e. cellulose derivatives) also exhibit biocompatibility, as well as film-forming properties and transparency. In combination with the electrical properties of PPy, these features make PPy/macromolecular cellulose composites suitable for applications as displays, lighting, and photovoltaics. Due to their chemical structure, macromolecular wood derivatives have been proposed with success as enhancing conductivity additives in Py polymerisation. The aim of the present review is to provide an overview of PPy chemistry and of the most relevant advances attained in the production of PPy/wood derived materials conducting composites

Use of a Novel Extremophilic Xylanase for an Environmentally Friendly Industrial Bleaching of Kraft Pulps

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.Peer reviewe

Extremozymes for wood-based building blocks: from pulp mill to board and insulation products – WoodZymes project

4 páginas.- 4 referencias.- Comunicación oral presentada en el 16th European Workshop on Lignocellulosics and Pulp (EWLP) Gothenburg, Sweden, June 28 – July 1, 2022Enzymes can substitute harsh and energy-demanding chemical treatments for production of bio-based building blocks and products from wood processing. However, their properties need to be adapted to the extreme operation conditions (such as high T and pH) commonly used by these industries. Here, we summarize the main results obtained during the WoodZymes European Project (www.woodzymes.eu), which aimed to provide tailor-made extremozymes and extremozyme-based processes never assayed before in wood biorefineries. Novel extremophilic enzymes active on kraft lignin (laccases) and xylan (xylanases) were developed and produced at pilot or industrial scales. The enzymatic fractionation of kraft lignins using the METNINTM lignin refining technology, and the extremozyme-aided delignification and bleaching of kraft pulps were demonstrated at pilot scale. The resulting lignin and hemicellulose derived compounds were chemically characterized and applied as components of phenol-(lignin)-formaldehyde resins for wood panels and of polyurethane foams, or as papermaking additives. The new extremozymes were also applied to improve some of the latter applications. The techno-economic and environmental assessment of the new materials and processes, developed in WoodZymes project, showed that extremozyme-based processes led to clear benefits in energy savings during the refining of pulp or wood fibres, enabled lower addition of harsh chemicals (e.g. ClO2 during pulp bleaching), and resulted in a lower carbon footprint of the new bio-based products by substitution of fossil-derived components.WoodZymes project was 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 ConsortiumN

Caractérisation des chromophores dans les pates cellulosiques écrues et de leurs impacts sur l'aptitude au blanchiment

Les sites industriels de production de pâte à papier sont confrontés à des problèmes de blanchiment conduisant à des sur-consommations en réactifs chimiques. Les travaux présentés dans cette thèse ont permis d'identifier l'origine de différents composés colorés présents dans les pâtes kraft écrues et d'évaluer leurs impacts sur l'aptitude au blanchiment. La couleur des pâtes kraft écrues peut provenir de la lignine résiduelle, de la coloration des hydrates de carbone soumis à des conditions de cuisson kraft, de la lignine précipitée en fin de cuisson, et/ou de l'adsorption de lignine dissoute sur les fibres durant la cuisson. Les chromophores formés sur les hydrates de carbone sont facilement éliminés par des traitements conventionnels de blanchiment impliquant de faibles charges en réactifs. La lignine précipitée ne semble pas être plus difficile à éliminer que la lignine résiduelle lors d'une séquence de blanchiment classique. En revanche, une pâte enrichie en lignine au cours de la cuisson peut conduire à des problèmes d'aptitude au blanchiment. Les problèmes de blanchiment peuvent s'expliquer par la formation, lors de la cuisson, de liaisons covalentes stables entre la lignine et les hydrates de carbone. Des analyses spectroscopiques ont révélé qu'il est possible de corréler la concentration relative de lignine en surface des fibres avec l'aptitude au blanchiment. La lignine de surface liée au substrat peut jouer un effet barrière limitant l'efficacité des réactifs de blanchiment.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Etude de la réduction de la consommation énergétique du raffinage des pâtes chimique par traitement enzymatique

Le raffinage des pâtes chimiques blanchies est de première importance pour produire des papiers suffisamment résistants répondant aux exigences de production sur machine et de qualité. Cette étape permet de modifier les caractéristiques morphologiques des fibres, d'améliorer la formation de la feu ille et d'augmenter les résistances mécaniques du papier. Le raffinage requiert jusqu'à 30% de la consommation totale d'une usine de production de papiers; en conséquence, des solutions visant à réduire la facture énergétique de ce poste sont recherchées. Dans ce contexte, l'utilisation d'enzymes dans le processus de préparation des fibres est une de ces solutions respectueuse de l'environnement. Des enzymes présentant des actions ciblées sur les composants de la paroi des fibres ont été appliquées à des pâtes commerciales blanchies issues de la cuisson de mélanges de résineux et de la cuisson d'eucalyptus brésilien avant raffinage. Grâce à ces travaux, l'impact du traitement enzymatique sur l'organisation des composés de la paroi et les propriétés des fibres a été évalué et quantifié. Les résultats diffèrent d'une enzyme à l'autre. Les enzymes ayant une activité cellobiohydrolase, xylanase ou mannanase ont présenté une action limitée. Peu de changements été observés. Seul le traitement par une xylanase a permis une amélioration de blancheur. Les cellu1ases présentant une activité endoglucanase majoritaire ont conduit à une ouverture de la structure des fibres, une augmentation de la proportion d'eau liée et de la résistance à la rupture du papier. L'observation en microscopie électronique couplé à de l'immunomarquage a par ailleurs permis de mettre en évidence la pénétration de cette enzyme au coeur de la paroi de la fibre. Toutefois, dans le cas de la pâte de résineux, la longueur des fibres a fortement été réduite. L'optimisation des conditions de traitement mécanique au travers d'une diminution de l'intensité de raffinage et de la quantité d'enzymes appliquée a permis de limiter la perte de résistance au déchirement consécutive à cette coupe. Dans ces conditions, en acceptant une diminution des résistances de 10% pour la rupture et de 13% pour le déchirement, une économie d'énergie de raffinage de 40% devient possible. Dans le cas de la pâte d'eucalyptus, les endoglucanases ont généré les effets les plus importants avec une augmentation de la résistance des feuilles et une égouttabilité supérieure. Avec un raffinage enzymatique optimisé, il devient possible de réduire de 45% la consommation d'énergie pour atteindre une résistance à la rupture de la feuille de papier de 4km (longueur de rupture)To produce papers matching with the requirements of paper machines and customers , it is of of the utmost importance to refine bleached chemical pulps. This stage allows modifying the morphological characteristics of fibres, to improve the paper formation and to develop the mechanical resistance of paper. The refining requires up to 30 % of the total energy consumption of a paper mill. Consequently, it is a key issue to look for solutions aiming at reducing the energy bill of this post. In this context, the addition of enzymes in the process could be one of these environmentally friendly solutions. The enzymes chosen, introduced before refining, have a specific action on the fibre wall chemid ll components of bleached kraft pulps which have been obtained from a mix of softwood or fram Brazilian eucalyptus. Results of introducing the enzyme allowed assessment and quantification of the impact of the enzyme treatment on fibre compounds organization and praperties. The consequences of the enzyme treatment differed from an enzyme to another one. Enzymes presenting an activity cellobiohydrolase, xylanase or mannanase had limited effects. Changes were too narrow to be noticed. Xylanase treatment only resulted in an improvement in pulp brightness. Cellulases presenting major endoglucanase activity opened the structure of fibres, increasing the proportion of linked water in the wall and the tensile strength of paper. Observations with electron microscopy coupled with immunolabelling technique showed the penetration of this enzyme through the fibre wall. Nevertheless, in the case of softwood pulp, fibre length dropped. The optimization of the enzyme amount and the mechanical treatment through a reduction of the refining intensity, reduced tear strength losses. In these conditions, if a reduction of 10 % of tensile strength and 13 % of tear strength can be tolerated, 40 % of refining energy could be saved. ln the case of eucalyptus pulp, endoglucanases generated the most important effects with an improvement of the paper resistance and a better drainage. With an optimizedenzymatic refining, it became possible to reduce the energy consumption by 45 % to reach 4km of breaking length, while maintaining high levels in the other relevant parameters.AIX-MARSEILLE1-BU Sci.St Charles (130552104) / SudocSudocFranceF

Utilisation des biotechnologies pour la valorisation des pailles de plantes annuelles en fibres papetières et composés phénoliques à haute valeur ajoutée

Les pailles de blé et de lin oléagineux ont été étudiées comme matière première pour la production de fibres papetières. Pour valoriser ces sous-produits agricoles, deux voies de valorisations ont été mises en place : la récupération des fibres de celluloses pour la fabrication de papier et la capacité à extraire les composés phénoliques. La connaissance des pailles a été approfondie afin de mieux connaître leur ultrastructure et les concentrations en composés phénoliques extractibles. L'acide férulique, l'acide coumarique, l'acide vanillique et la vanilline ont été retenus comme composés phénoliques à haute valeur ajoutée. Des pré-traitements enzymatiques par la féruloyl estérase et des xylanases, enzymes connues pour leur aide à la délignification, ont été testées. Ces pré-traitements enzymatiques augmentent la libération des composés phénoliques, déstructurent les hémicelluloses et la lignine et améliorent les conditions de cuissons papetières en réduisant les charges chimiques utilisées et en augmentant les propriétés mécaniques des pâtes. Afin de mieux comprendre l'action des enzymes et de visualiser la FAE sur son substrat, des analyses basées sur des observations au microscope électronique à transmission ont pu être développées. Ainsi la localisation de la féruloyl estérase dans les pailles traitées a pu être montrée. Les pâtes obtenues ont ensuite été blanchies par différentes séquences TCF (peroxyde d'hydrogène, acide peracétique, ozone) et par des séquences enzymatiques (féruloyl estérase, xynalases, laccases, aryl alcool oxydase) plus soucieuses de l'environnement. Les pailles de blé et de lin oléagineux ont montré une bonne aptitude au blanchimentAIX-MARSEILLE1-BU Sci.St Charles (130552104) / SudocSudocFranceF