Scale-up of a novel non-enzymatic cellulose-to-glucose hydrolysis process

The acidic hydrolysis of cellulose to glucose followed by its subsequent fermentation to ethanol has been an intensive research topic over the last decades. On a global scale, cellulosic resources are by far the most promising alternative to first generation starch for bioethanol production. However, such processes are still struggling to reach economy due to the high investment (CAPEX) and operating costs (OPEX) required especially in a market where fossil fuels are so affordable (Feb 2016). Despite the severe restrictions associated with the production of second generation sugars (assuming a target price comparable to sugar at $5.96 USD/kg – Feb. 2016), a patented three-step method developed by the Industrial Research Chair on Cellulosic Ethanol and Biocommodities (CRIEC-B) shows significant potential to counter the classical restrictions associated with such process. The first step of the process is performed in concentrated acidic solution resulting in a decrystallization of the cellulose macromolecule, then the mixture is treated again (post-hydrolysis) at higher temperature allowing conversion of cellulose to glucose. After a patented separation step, the reactants are isolated from the carbohydrates allowing an optimal recuperation of the chemicals used for the reaction. As well, optimization of this process was performed in order to maximize glucose production while minimizing operation as well as fermentation inhibitors. In order to understand the parameters of this process, the decrystallized cellulose was analyzed using XRD and SEM in order to determine the minimum liquid/solid ratio needed for the process. In addition, the post-hydrolysis step was optimized using experimental design in order to maximize glucose yield while minimizing water consumption. After hydrolysis, the glucose solutions were fermented into ethanol at high yield using a commercial grade non-GMO yeast. Hydrolysis was performed on several biomasses such as softwood cellulose and hemp cellulose. Finally, a scaled-up pilot plant based on this process is currently being designed in order to validate the economic viability of this process at larger scale as well as to verify the constraints generated from a scale modification. The targeted pilot facilities will be used for the hydrolysis of cellulose in order to produce a system with a total capacity of 100 000L/y. One of the main challenge of this scale-up is the high corrosiveness of the media associated with the other restrictions and chemicals used in the process as well as the high viscosity occurring when cellulose is originally destructured. In this work, investigations were made in order to find a low cost corrosive and solvent-resistant material that could be used in the temperature range corresponding to the process. The end game will be to validate cost-effective process for the production of second-generation bioethanol from cellulosic resources

GC-Content evolution in bacterial genomes: The biased gene conversion hypothesis expands

The characterization of functional elements in genomes relies on the identification of the footprints of natural selection. In this quest, taking into account neutral evolutionary processes such as mutation and genetic drift is crucial because these forces can generate patterns that may obscure or mimic signatures of selection. In mammals, and probably in many eukaryotes, another such confounding factor called GC-Biased Gene Conversion (gBGC) has been documented. This mechanism generates patterns identical to what is expected under selection for higher GC-content, specifically in highly recombining genomic regions. Recent results have suggested that a mysterious selective force favouring higher GC-content exists in Bacteria but the possibility that it could be gBGC has been excluded. Here, we show that gBGC is probably at work in most if not all bacterial species. First we find a consistent positive relationship between the GC-content of a gene and evidence of intra-genic recombination throughout a broad spectrum of bacterial clades. Second, we show that the evolutionary force responsible for this pattern is acting independently from selection on codon usage, and could potentially interfere with selection in favor of optimal AU-ending codons. A comparison with data from human populations shows that the intensity of gBGC in Bacteria is comparable to what has been reported in mammals. We propose that gBGC is not restricted to sexual Eukaryotes but also widespread among Bacteria and could therefore be an ancestral feature of cellular organisms. We argue that if gBGC occurs in bacteria, it can account for previously unexplained observations, such as the apparent non-equilibrium of base substitution patterns and the heterogeneity of gene composition within bacterial genomes. Because gBGC produces patterns similar to positive selection, it is essential to take this process into account when studying the evolutionary forces at work in bacterial genomes

Simulation numérique directe des écoulements liquide-gaz avec évaporation (application à l'atomisation)

Le but de cette thèse est d'étudier numériquement les écoulements diphasiques liquide-gaz à l'aide d'une méthode de suivi d'interface précise. Tout d'abord, nous mettons en place une configuration turbulence homogène isotrope diphasique. Cette configuration est utilisée pour étudier la turbulence liquide-gaz ainsi que le modèle ELSA. A l'aide de la simulation présentée il a été possible de déterminer les constantes de modélisation et de valider les termes sources utilisés dans la zone dense du spray. Ensuite, le phénomène d'évaporation est étudié en utilisant dans un premier temps un scalaire passif puis en utilisant un formalisme DNS d'évaporation. Les équations d'énergie et des espèces ont été ajoutées dans le code ARCHER. La validation de la DNS d'évaporation a été réalisée en comparant nos résultats aux solutions théoriques, tel que la loi du D2. Les limitations et les apports de cette approche sont finalement discutés et des perspectives d'améliorations sont proposées.The aim of this thesis is to study numerically two phase flow using accurate interface tracking method. First, a two phase flow homogeneous isotropic turbulence is performed. This numerical configuration is used to study two phase flows turbulence and the ELSA model used in primary atomization modelling. Based on these results, modelling constants and source terms have been determined and validated. Then the evaporation process is studied and modelized by using a passive scalar and then by using a DNS formalism. Energy and species equations are added in the ARCHER code. Validation of the DNS performed by comparing the DNS results with theorical solution, such as the D2 law. Finally, limitations and interests of this approach are discussed and further improvements are proposed.ROUEN-INSA Madrillet (765752301) / SudocSudocFranceF

Where does the drop size distribution come from?

[EN] This study employs DNS of two-phase flows to enhance primary atomization understanding and modelling to be used in numerical simulation in RANS or LES framework. In particular, the work has been aimed at improving the information on the liquid-gas interface evolution available inside the Eulerian-Lagrangian Spray Atomization (ELSA) framework. Even though this approach has been successful to describe the complete liquid atomization process from the primary region to the dilute spray, major improvements are expected on the establishment of the drop size distribution (DSD). Indeed, the DSD is easily defined once the spray is formed, but its appearance and even the mathematical framework to describe its creation during the initial breakup of the continuous liquid phase in a set of individual liquid parcels is missing. This is the main aim of the present work to review proposals to achieve a continuous description of the DSD formation during the atomization process. The attention is here focused on the extraction from DNS data of the behaviour of geometrical variable of the liquidgas interface, such as the mean and Gauss surface curvatures. A DNS database on curvature evolution has been generated. A Rayleigh-Plateau instability along a column of liquid is considered to analyse and to verify the capabilities of the code in correctly predicting the curvature distribution. A statistical analysis on the curvatures data, in terms of probability density function, was performed in order to determine the physical parameters that control the curvatures on this test case. Two different methods are presented to compute the curvature distribution and in addition, the probability to be at a given distance of the interface is studied. This approach finally links the new tools proposed to follow the formation of the spray with the pioneering work done on scale distribution analysis.Canu, R.; Dumouchel, C.; Duret, B.; Essadki, M.; Massot, M.; Ménard, T.; Puggelli, S.... (2017). Where does the drop size distribution come from?. En Ilass Europe. 28th european conference on Liquid Atomization and Spray Systems. Editorial Universitat Politècnica de València. 605-612. https://doi.org/10.4995/ILASS2017.2017.4706OCS60561

Internal Numerical Simulation of a Swirl Simplex Atomizer to Predict Atomization Outputs

International audienc

The abundant extrachromosomal DNA content of the Spiroplasma citri GII3-3X genome

<p>Abstract</p> <p>Background</p> <p><it>Spiroplama citri</it>, the causal agent of citrus stubborn disease, is a bacterium of the class <it>Mollicutes </it>and is transmitted by phloem-feeding leafhopper vectors. In order to characterize candidate genes potentially involved in spiroplasma transmission and pathogenicity, the genome of <it>S. citri </it>strain GII3-3X is currently being deciphered.</p> <p>Results</p> <p>Assembling 20,000 sequencing reads generated seven circular contigs, none of which fit the 1.8 Mb chromosome map or carried chromosomal markers. These contigs correspond to seven plasmids: pSci1 to pSci6, with sizes ranging from 12.9 to 35.3 kbp and pSciA of 7.8 kbp. Plasmids pSci were detected as multiple copies in strain GII3-3X. Plasmid copy numbers of pSci1-6, as deduced from sequencing coverage, were estimated at 10 to 14 copies per spiroplasma cell, representing 1.6 Mb of extrachromosomal DNA. Genes encoding proteins of the TrsE-TraE, Mob, TraD-TraG, and Soj-ParA protein families were predicted in most of the pSci sequences, in addition to members of 14 protein families of unknown function. Plasmid pSci6 encodes protein P32, a marker of insect transmissibility. Plasmids pSci1-5 code for eight different <it>S. citri </it>adhesion-related proteins (ScARPs) that are homologous to the previously described protein P89 and the <it>S. kunkelii </it>SkARP1. Conserved signal peptides and C-terminal transmembrane alpha helices were predicted in all ScARPs. The predicted surface-exposed N-terminal region possesses the following elements: (i) 6 to 8 repeats of 39 to 42 amino acids each (sarpin repeats), (ii) a central conserved region of 330 amino acids followed by (iii) a more variable domain of about 110 amino acids. The C-terminus, predicted to be cytoplasmic, consists of a 27 amino acid stretch enriched in arginine and lysine (KR) and an optional 23 amino acid stretch enriched in lysine, aspartate and glutamate (KDE). Plasmids pSci mainly present a linear increase of cumulative GC skew except in regions presenting conserved hairpin structures.</p> <p>Conclusion</p> <p>The genome of <it>S. citri </it>GII3-3X is characterized by abundant extrachromosomal elements. The pSci plasmids could not only be vertically inherited but also horizontally transmitted, as they encode proteins usually involved in DNA element partitioning and cell to cell DNA transfer. Because plasmids pSci1-5 encode surface proteins of the ScARP family and pSci6 was recently shown to confer insect transmissibility, diversity and abundance of <it>S. citri </it>plasmids may essentially aid the rapid adaptation of <it>S. citri </it>to more efficient transmission by different insect vectors and to various plant hosts.</p

Liquefaction of bark for the development of new products for wood preservation

Les travaux de recherche présentés portent sur l'utilisation des produits de la liquéfaction des écorces d'épicéa dans le phénol pour la préservation du bois. Les produits de la liquéfaction permettent la synthèse d'une résine thermodurcissable de type phénolique. Les résines formulées sont imprégnées dans le bois suivi d'un durcissement in situ. Un prétraitement est mis au point dans le but d'enrichir la fraction phénolique des écorces. Ce prétraitement consiste à hydrolyser les polysaccharides principalement la cellulose et les hémicelluloses dans une solution acide. Ce prétraitement permet d'obtenir un taux de lignine dans les écorces de 60 %, et un taux de cellulose de 28 %. Un procédé de liquéfaction dans un système composé de phénol, d'eau et d'éthanol est optimisé dans le but d'obtenir des taux de liquéfaction supérieur à 85 %, et un taux d'écorces liquéfiées par rapport à la masse de phénol supérieur à 50 %. Les produits de la liquéfaction présentent l'avantage de polymériser sans ajout de formaldéhyde. La durabilité conférée au bois par les résines est bonne, surtout pour les résines phénol/formaldéhyde. Les résines sont peu lessivables. L'imprégnation du bois par les résines provoque un gonflement du bois ce qui améliore la stabilité dimensionnelle de ce dernierThis work focuses on the use of liquefaction products of spruce bark in phenol for the wood preservation. The liquefaction products allow the synthesis of phenolic thermosetting resins. The formulated resins were impregnated into the wood followed by in situ polymerization. A pretreatment was developed in order to increase the phenolic compounds in the spruce bark. This step is an acid hydrolysis of polysaccharides. This pretreatment allowed obtaining a Klason lignin content of 60 %, and a cellulose content of 28 %. A liquefaction process was developed in a mixture of solvent composed of phenol, ethanol, and water. The optimized experimental conditions allowed obtaining a liquefaction yield superior to 85 %, with liqui?ed bark/phenol ratio superior to 50 %. The lique?ed products had the advantage to polymerize without formaldehyde. The resins enhanced the wood durability especially for the phenol/formaldehyde resins. The leaching was low. The wood impregnation allowed a wood swelling, thereby the impregnated wood had a better dimensional stabilit

Liquéfaction d'écorces en vue de leur valorisation pour le développemnt de nouveaux produits de traitement du bois

This work focuses on the use of liquefaction products of spruce bark in phenol for the wood preservation. The liquefaction products allow the synthesis of phenolic thermosetting resins. The formulated resins were impregnated into the wood followed by in situ polymerization. A pretreatment was developed in order to increase the phenolic compounds in the spruce bark. This step is an acid hydrolysis of polysaccharides. This pretreatment allowed obtaining a Klason lignin content of 60 %, and a cellulose content of 28 %. A liquefaction process was developed in a mixture of solvent composed of phenol, ethanol, and water. The optimized experimental conditions allowed obtaining a liquefaction yield superior to 85 %, with liqui?ed bark/phenol ratio superior to 50 %. The lique?ed products had the advantage to polymerize without formaldehyde. The resins enhanced the wood durability especially for the phenol/formaldehyde resins. The leaching was low. The wood impregnation allowed a wood swelling, thereby the impregnated wood had a better dimensional stabilityLes travaux de recherche présentés portent sur l'utilisation des produits de la liquéfaction des écorces d'épicéa dans le phénol pour la préservation du bois. Les produits de la liquéfaction permettent la synthèse d'une résine thermodurcissable de type phénolique. Les résines formulées sont imprégnées dans le bois suivi d'un durcissement in situ. Un prétraitement est mis au point dans le but d'enrichir la fraction phénolique des écorces. Ce prétraitement consiste à hydrolyser les polysaccharides principalement la cellulose et les hémicelluloses dans une solution acide. Ce prétraitement permet d'obtenir un taux de lignine dans les écorces de 60 %, et un taux de cellulose de 28 %. Un procédé de liquéfaction dans un système composé de phénol, d'eau et d'éthanol est optimisé dans le but d'obtenir des taux de liquéfaction supérieur à 85 %, et un taux d'écorces liquéfiées par rapport à la masse de phénol supérieur à 50 %. Les produits de la liquéfaction présentent l'avantage de polymériser sans ajout de formaldéhyde. La durabilité conférée au bois par les résines est bonne, surtout pour les résines phénol/formaldéhyde. Les résines sont peu lessivables. L'imprégnation du bois par les résines provoque un gonflement du bois ce qui améliore la stabilité dimensionnelle de ce dernie

Liquéfaction d'écorces en vue de leur valorisation pour le développemnt de nouveaux produits de traitement du bois

Les travaux de recherche présentés portent sur l'utilisation des produits de la liquéfaction des écorces d'épicéa dans le phénol pour la préservation du bois. Les produits de la liquéfaction permettent la synthèse d'une résine thermodurcissable de type phénolique. Les résines formulées sont imprégnées dans le bois suivi d'un durcissement in situ. Un prétraitement est mis au point dans le but d'enrichir la fraction phénolique des écorces. Ce prétraitement consiste à hydrolyser les polysaccharides principalement la cellulose et les hémicelluloses dans une solution acide. Ce prétraitement permet d'obtenir un taux de lignine dans les écorces de 60%, et un taux de cellulose de 28%. Un procédé de liquéfaction dans un système composé de phénol, d'eau et d'éthanol est optimisé dans le but d'obtenir des taux de liquéfaction supérieur à 85%, et un taux d'écorces liquéfiées par rapport à la masse de phénol supérieur à 50 %. Les produits de la liquéfaction présentent l'avantage de polymériser sans ajout de formaldéhyde. La durabilité conférée au bois par les résines est bonne, surtout pour les résines phénol/formaldéhyde. Les résines sont peu lessivables. L'imprégnation du bois par les résines provoque un gonflement du bois ce qui améliore la stabilité dimensionnelle de ce dernierThis work focuses on the use of liquefaction products of spruce bark in phenol for the wood preservation. The liquefaction products allow the synthesis of phenolic thermosetting resins. The formulated resins were impregnated into the wood followed by in situ polymerization. A pretreatment was developed in order to increase the phenolic compounds in the spruce bark. This step is an acid hydrolysis of polysaccharides. This pretreatment allowed obtaining a Klason lignin content of 60 %, and a cellulose content of 28%. A liquefaction process was developed in a mixture of solvent composed of phenol, ethanol, and water. The optimized experimental conditions allowed obtaining a liquefaction yield superior to 85 %, with liquified bark/phenol ratio superior to 50 %. The liquefied products had the advantage to polymerize without formaldehyde. The resins enhanced the wood durability especially for the phenol/formaldehyde resins. The leaching was low. The wood impregnation allowed a wood swelling, thereby the impregnated wood had a better dimensional stabilityMETZ-SCD (574632105) / SudocNANCY1-Bib. numérique (543959902) / SudocNANCY2-Bibliotheque electronique (543959901) / SudocNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF