References of "Simon, Mathilde"
     in
Bookmark and Share    
See detailOptimization of a formic/acetic acid treatment of beech wood for lignin extraction
Simon, Mathilde ULg; Richel, Aurore ULg; Vanderghem, Caroline ULg et al

Conference (2012, August)

Lignocellulosic substrates are a promising alternative resource for the sustainable production of energy (biofuels), bio-based products and organic compounds. In the past, the extraction and recycling of ... [more ▼]

Lignocellulosic substrates are a promising alternative resource for the sustainable production of energy (biofuels), bio-based products and organic compounds. In the past, the extraction and recycling of cellulose (into fermentable glucose) constituted the central axis of lignocellulosic biorefinery processes. Degraded hemicelluloses and lignins were recovered as side-products with no possibilities of high-added value applications. Within the context of an integrated biorefinery, and for economic reasons, the recovery and the non-energetic valorization of lignins have opened recently new horizons. Lignin is a cross-linked phenolic polymer and is considered as potential alternative to petrochemical polymers or as a source of antioxidants for cosmetics and food industry, resins, chelating agent... As the final application of lignin depends on both extraction process and type of lignocellulosic sources, the development of fast and efficient physicochemical characterization methods is thus a prerequisite to optimize extraction processing conditions. In this study, beech wood particles (Fagus sylvatica L.) are delignified at atmospheric pressure by a formic acid/acetic acid/water mixture. Firstly, response surface methodology is used to optimize cooking time and temperature for delignification, pulp yield and concentration of degradation products (2-furfural and 5-hydroxymethylfurfural). The results highlight that best delignification is obtained in the highest cooking times and temperatures and that 5-hydroxymethylfurfural is produced during the formic/acetic acid treatment but is also degraded into 2-furfural. With the aim to develop an integrated biorefinery approach, multi-criteria optimization is used to find ideal cooking time and temperature (5h07, 104.2°C) leading to the maximization of delignification and pulp yield and to the minimization of 2-furfural production Finally, physicochemical and chemical structures of extracted lignins are found dependent on treatment conditions harshness. [less ▲]

Detailed reference viewed: 79 (24 ULg)
Full Text
Peer Reviewed
See detailEvaluation of Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for second-generation lignin analysis
Richel, Aurore ULg; Vanderghem, Caroline ULg; Simon, Mathilde ULg et al

in Analytical Chemistry Insights (2012), 7

Matrix-Assisted Laser Desorption/Ionization time-of-flight (MALDI-TOF) mass spectrometry is evaluated as an elucidation tool for structural features and molecular weights estimation of some extracted ... [more ▼]

Matrix-Assisted Laser Desorption/Ionization time-of-flight (MALDI-TOF) mass spectrometry is evaluated as an elucidation tool for structural features and molecular weights estimation of some extracted herbaceous lignins. Optimization of analysis conditions, using a typical organic matrix, namely CHCA (alpha-cyano-4-hydroxycinnamic acid), in combination with alpha-cyclodextrine, allows efficient ionization of poorly soluble lignin materials and suppression of matrix-related ions background. Analysis of low-mass fragments ions (m/z 100-600) in the positive ion mode offers a “fingerprint” of starting lignins that could be a fine strategy to qualitatively identify principal interunit linkages between phenylpropanoid units. The molecular weights of lignins are estimated using size exclusion chromatography and compared to MALDI-TOF-MS profiles. Miscanthus (Miscanthus x giganteus) and Switchgrass (Panicum Virgatum L.) lignins, recovered after a formic acid/acetic acid/water process or aqueous ammonia soaking, are selected as benchmarks for this study. [less ▲]

Detailed reference viewed: 41 (16 ULg)
Full Text
Peer Reviewed
See detailImpact of a formic/acetic acid treatment of beech wood on delignification and chemical structure of lignins
Simon, Mathilde ULg; Richel, Aurore ULg; Vanderghem, Caroline ULg et al

Conference (2011)

Lignocellulosic substrates constitute a promising alternative resource for the sustainable production of energy (biofuels), biobased products and organic compounds. In the past, the extraction and the ... [more ▼]

Lignocellulosic substrates constitute a promising alternative resource for the sustainable production of energy (biofuels), biobased products and organic compounds. In the past, the extraction and the valorization of cellulose (into fermentescible glucose) constituted the central axis of lignocellulosic biorefinery processes. Degraded hemicelluloses and lignins were however recovered as side-products with no possibilities of high-added value applications. Within the context of an integrated biorefinery, and for economic reasons, the recovery and the non-energetic transformation of lignins have opened recently new horizons. Lignin is a cross-linked phenolic polymer and is considered as a potential alternative to petrochemical polymers or as a source of antioxidants for cosmetics and food industry, resins, chelating agent... As the final application of lignin is dependent of both extraction process and type of lignocellulosic sources, the development of fast and efficient physicochemical characterization methods is thus a prerequisite to optimize extraction processing conditions. In this study, beech wood particles (Fagus sylvatica L.) collected in the region of Gaume (Belgium) were delignified at atmospheric pressure by a mixture of formic acid/acetic acid/water. The effect of cooking time and temperature was evaluated on delignification and on chemical structure of lignins obtained by precipitation from the black liquor after treatments. To study the delignification, a central composite design and response surface methodology were used for the optimization of two treatments parameters, i.e. time (between 1h30 and 4h30) and temperature (from 87 to 107°C). These two variables were optimized for delignification yield, pulp yield, concentration of degradation products (furfural and hydroxymethylfurfural) and for the amount of residual linkages between lignin constitutive units. On the basis of our results, higher delignification yields were obtained when cooking time and temperature increased. However, for high cooking times and temperatures, pulp yield decreased because hemicelluloses and cellulose were hydrolyzed and the production of furfural and hydroxymethylfurfural was augmented. The structural and physico-chemical features of extracted lignins were investigated with different analytical tools, namely infrared spectrometry, thermogravimetric analysis, size-exclusion chromatography, mono-dimensional nuclear magnetic resonance (NMR 1H and NMR 13C) and bidimensional NMR (heteronuclear HSQC experiments). The characterization of lignins indicated the occurrence of a repolymerization phenomenon when both cooking time and temperature increased. Indeed, HSQC NMR spectra presented oxidized syringyl units. Otherwise, thermogravimetric analysis and HSQC analysis showed the presence of hemicelluloses in lignin samples from soft treatments (1h30, 87°C). Some linkages between lignin and hemicelluloses were not cleaved under these experimental conditions. [less ▲]

Detailed reference viewed: 54 (16 ULg)
Full Text
See detailImpact of the treatment conditions of a formic/acetic acid delignification method on chemical structure and antioxidant activity of beech wood lignin
Simon, Mathilde ULg; Vanderghem, Caroline ULg; Richel, Aurore ULg et al

Poster (2011)

The interest in lignocellulosic substrates is increasing because they are clearly identified for their high potential of development in energy and value-added molecules production. Indeed lignocellulosic ... [more ▼]

The interest in lignocellulosic substrates is increasing because they are clearly identified for their high potential of development in energy and value-added molecules production. Indeed lignocellulosic biomass constitutes a promising resource for a sustainable production of organic compounds and biobased products that could progressively replace molecules from the petrochemical industry. Until now lignocellulosic substrates were mainly used for the valorization of cellulose. Hemicelluloses and lignins were less valorized and often degraded after the process. However, due to their phenolic structure, lignins can be valorized in a lot of high-valued applications like vanillin production, replacement of petrochemical polymers, antioxidants for cosmetics and food industry, resins… In this study, a representative sample of beech wood (Fagus sylvatica L.) was collected in the region of Gaume in Belgium. Beech wood was delignified at atmospheric pressure by an organosolv process using a mixture of formic acid/acetic acid/water. The effect of cooking time and temperature was evaluated on the structure, physico-chemical properties and antioxidant activity of the lignins obtained from the black liquor after treatments. The structural and physico-chemical characteristics of the lignins were investigated with different tools like infrared spectrometry, thermogravimetric analysis, gel permeation chromatography after acetylation of lignins, NMR 1H, 13C and HSQC. The antioxidant activity was assessed by a spectrophotometric method using the α,α-diphenyl-β-picrylhydrazyl radical (DPPH). [less ▲]

Detailed reference viewed: 46 (10 ULg)
Full Text
See detailOptimization of a formic/acetic acid treatment of beech wood (Fagus sylvatica L.) for delignification
Simon, Mathilde ULg; Richel, Aurore ULg; Vanderghem, Caroline ULg et al

Poster (2011)

Lignin is a promising molecule constituting a renewable alternative to some petrochemical industry products. Lignin is an aromatic cross-linked heteropolymer composed of three phenylpropanoids (p ... [more ▼]

Lignin is a promising molecule constituting a renewable alternative to some petrochemical industry products. Lignin is an aromatic cross-linked heteropolymer composed of three phenylpropanoids (p-hydroxyphenyl, guaiacyl and syringyl units) linked together via radical coupling reactions by specific ether or carbon-carbon bonds. With this phenylpropanoid structure, lignin is a rich resource of biobased products that could find high-valued applications in a lot of different areas like petrochemical polymer reinforcement and replacement, antioxidants, stabilizers, resins and vanillin production... The first challenge of the valorization of lignins is their extraction from raw materials. Lignins can be found in different lignocellulosic substrates like grasses, softwood and hardwood. This extraction process needs the development of suitable biomass treatments, allowing efficient lignin recuperation without degradation. This one could lead to the loss of some interesting properties and so of some valorization possibilities. In this study, beech wood (Fagus sylvatica L.) was collected in the region of Gaume (Belgium). Beech wood particles were delignified at atmospheric pressure by a mixture of formic acid/acetic acid/water. A central composite design and response surface methodology were used for the optimization of treatment parameters for delignification. The optima of two independent variables, namely time (1h30, 3h, 4h30) and temperature (87°C, 97°C, 107°C), were determined on delignification yield, pulp yield, concentration of degradation products (furfural and hydroxymethylfurfural). Moreover, the impact of these two variables on the amount of residual linkages between phenylpropanoid units was evaluated by semi-quantitative bidimensional nuclear magnetic resonance spectroscopy (NMR-HSQC). Our results highlight that the delignification yields increase when cooking time and temperature are elevated. Nevertheless, under these conditions, pulp yield decreases as hydrolysis of hemicelluloses and cellulose occurs. The hydrolysates of carbohydrates (free sugars or oligosaccharides) are contained in the black liquor. At elevated temperature and time, the amount of degradation products in the black liquor is increased. [less ▲]

Detailed reference viewed: 48 (9 ULg)
Full Text
See detailProduction d'oligosaccharides à partir de gomme de caroube
Simon, Mathilde ULg

Master's dissertation (2010)

The general framework of this study is the discovery of prebiotics and more specifically the production of oligosaccharides by enzymatic hydrolysis of locust bean gum. These, though not much studied ... [more ▼]

The general framework of this study is the discovery of prebiotics and more specifically the production of oligosaccharides by enzymatic hydrolysis of locust bean gum. These, though not much studied, could present a rich prebiotics potential. The aim of this work was the purification of beta-mannanases located in germinating carob seeds as well as the validation of a AEC-PAD method applicable to the analysis of locust bean gum hydrolysates. Therefore, it has permitted to establish a concentration and purification procedure of beta-mannanases and to determine a suitable preservation method of enzymatic extracts. An original method to evaluate the enzymatic activity by viscosity measurements has also been developed and permits the study of the evolution of enzymatic activities during germination. The validation method of characterization and quantification of (galacto)-manno-oligosaccharides constitutes the last part studied. Seven performance criteria calculated for each of the nine standards were used to validate the method. It has then been used to analyze locust bean gum hydrolysates. The results of this work are the first of a new research theme. They offer many opportunities and future applications. [less ▲]

Detailed reference viewed: 157 (7 ULg)