References of "Jacquet, Nicolas"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailMonitoring the laccase reaction of vanillin and poplar hydrolysate
Sòti, Valentin; Jacquet, Nicolas ULg; Apers, Sandra et al

in Journal of Chemical Technology & Biotechnology (in press)

BACKGROUND: Laccase is an intensively researched enzyme for industrial use. Except for decolorisation measurements, HPLC analysis is the conventional method for monitoring the phenolic removal during ... [more ▼]

BACKGROUND: Laccase is an intensively researched enzyme for industrial use. Except for decolorisation measurements, HPLC analysis is the conventional method for monitoring the phenolic removal during laccase enzyme reaction. This paper reports an investigation of the continuous UV absorbance follow-up of the laccase reaction with steam pretreated poplar hydrolysate. RESULTS: Vanillin was used as a model substrate and lignocellulose xylose rich fraction (XRF) as a biologically complex substrate for laccase detoxification. The reaction was followed by HPLC-UV as well as by UV spectrometric measurements. Results suggest that the reaction can be successfully monitored by measuring the change of UV absorbance at 280 nm, without previous compound separation. In case of XRF experiments the spectrophotometric follow-up is especially useful, as HPLC analysis takes a long time and provides less information than in case of single substrates. The method seems to be suitable for optimization and process control. CONCLUSION: The obtained results can help to construct a fast, easy and straightforward monitoring system for laccase-phenolic substrate reactions. [less ▲]

Detailed reference viewed: 25 (8 ULg)
Full Text
Peer Reviewed
See detailScalable temperature induced stress for the large-scale production of functionalized Bifidobacteria
Nguyen, Huu Thanh ULg; Razafindralambo, Hary; Richel, Aurore ULg et al

in Journal of Industrial Microbiology & Biotechnology (in press)

The application of sub-lethal stresses is known to be an efficient strategy to enhance survival of probiotic bacteria during drying processes. In this context, we previously showed that the application of ... [more ▼]

The application of sub-lethal stresses is known to be an efficient strategy to enhance survival of probiotic bacteria during drying processes. In this context, we previously showed that the application of heat stress upon the entry into stationary phase increased significantly the viability of Bifidobacterium bifidum. However, this heat shock has been considered only in small scale bioreactor and no information is available for a possible scaling-up strategy. Five different operating scales (0.2 L, 2 L, 20 L, 200 L and 2000 L) have thus been tested and the results showed that the viability of B. bifidum increases from 3.15 to 6.57 folds, depending on the scale considered. Our observations pointed out the fact that the heat stress procedure is scalable according to the main outcome, i.e. increases in cell viability, but other factors have to be taken into account. Among these factors, dissolved carbon dioxide seems to play a significant role since it explain the differences observed between the test performed at lab-scale and in industrial conditions. [less ▲]

Detailed reference viewed: 52 (7 ULg)
Full Text
Peer Reviewed
See detailMetabolic profile of mixed culture acidogenic fermentation of lignocellulosic residues and the effect of upstream substrate fractionation by steam explosion
Perimenis, Anastasios; van Aarle, Ingrid; Nicolay, Thomas et al

in Biomass Conversion and Biorefinery (in press)

Lignocellulosic biomass residues have attracted attention for the sustainable production of molecules for material and energetic use through biochemical conversion. Their recalcitrant structure prevents a ... [more ▼]

Lignocellulosic biomass residues have attracted attention for the sustainable production of molecules for material and energetic use through biochemical conversion. Their recalcitrant structure prevents a broader use and asks for the development of sustainable techniques that can efficiently separate, recover and valorize the constituting components. In a cascading concept, residual streams of such processes can be further exploited in an attempt to valorize the largest possible fraction of the initial material. Three lignocellulosic substrates, namely dried sugar beet pulp, wheat bran and miscanthus straw, were upstream fractionated by steam explosion to extract the hemicellulose fraction. This study evaluated the valorization of the residual solid fraction through mixed acidogenic fermentation for the production of volatile fatty acids (VFA) as platform chemicals. Batch experiments have been conducted for the reference material (non-treated) and the solid fraction remaining after steam explosion, with and without the addition of an external mixed inoculum. Steam explosion residues contained less hemicellulose than the initial materials. The difference in the fermentation profile between steam explosion residues and non-treated substrates is dependent on the substrate. Maximum total VFA (tVFA) concentration was 18.8 gCOD/kgmixed_liquor, and maximum yield of chemical oxygen demand (COD) conversion into tVFAwas 33 % for the case of non-treated inoculated beet pulp. [less ▲]

Detailed reference viewed: 17 (0 ULg)
Full Text
Peer Reviewed
See detailGenotype contribution to the chemical composition of banana rachis and implications for thermo/biochemical conversion
Tiappi Deumaga, Mathias Florian; Happi Emaga, Thomas; Tchokouassom, Raphael et al

in Biomass Conversion and Biorefinery (in press)

Chemical composition of banana rachis from three varieties (Grande naine, Pelipita, and CRBP969) was ana- lyzed, and the genotype contribution to composition variabil- ity was investigated. Wet chemistry ... [more ▼]

Chemical composition of banana rachis from three varieties (Grande naine, Pelipita, and CRBP969) was ana- lyzed, and the genotype contribution to composition variabil- ity was investigated. Wet chemistry and instrumental analysis procedures (X-ray diffraction, 31P NMR spectroscopy, and thermogravimetry) were used. Some significant differences were found among the three genotypes: GN-AAA genotype was found to be significantly the highest in ash fraction (30.16 %) and the lowest in acid insoluble lignin (6.58 %) at 95 % confidence level. It showed also the highest content in potassium (43.5 % in ash). Implication of compositional dif- ferences on valorization efficiency by biochemical or thermo- chemical pathways was investigated. For this purpose, corre- lation coefficients between compositional characteristics and yields in volatile compounds from pyrolysis and glucose yields from enzymatic saccharification were analyzed. Ash content was revealed to be the main drawback parameter for volatile yields from pyrolysis (r = −0.93), while for glucose yields during saccharification were limited mainly by the con- tent in guaiacyl units of the lignin fraction (r = −0.98). How- ever, a strong and positive correlation was established be- tween the volatiles yield and the acid insoluble lignin content (r = 0.98) Thus, according to these observations and based on their compositional significant differences, GN-AAA was the better candidate for bioconversion pathway while PPT-ABB and CRBP969-AAAB samples were shown to be better can- didates for thermochemical conversion pathway. This work gives important preliminary information for considering ba- nana rachis as an interesting feedstock candidate for biorefinery. [less ▲]

Detailed reference viewed: 75 (31 ULg)
Full Text
Peer Reviewed
See detailComparative biochemical analysis after steam pretreatments of lignocellulosic biomass from six combined morphological parts of Williams Cavendish banana plant (Triploid Musa AAA group)
Kamdem, Irenée ULg; Jacquet, Nicolas ULg; Tiappi Deumaga, Mathias Florian ULg et al

in Waste Management & Research : The Journal of the International Solid Wastes & Public Cleansing Association (2015)

The accessibility of fermentable substrates to enzymes is a limiting factor for the efficient bioconversion of agricultural wastes in the context of sustainable development. This paper presents the ... [more ▼]

The accessibility of fermentable substrates to enzymes is a limiting factor for the efficient bioconversion of agricultural wastes in the context of sustainable development. This paper presents the results of a biochemical analysis performed on Williams Cavendish Lignocellulosic Biomass (WCLB) after steam cracking (SC) and steam explosion (SE) pretreatments. Solid (S) and liquid (L) fractions (Fs) obtained from SC pretreatment performed at 180°C (SLFSC180) and 210°C (SLFSC210) generated, after diluted acid hydrolysis, the highest proportions of neutral sugar (NS) contents, specifically 52.82±3.51 and 49.78±1.39 %w/w WCLB’s dry matter (DM), respectively. The highest proportions of glucose were found in SFSC210 (53.56±1.33 %w/w DM) and SFSC180 (44.47±0.00 %w/w DM), while the lowest was found in unpretreated WCLB (22.70±0.71 %w/w DM). Total NS content assessed in each LF immediately after SC and SE pretreatments was less than 2 %w/w of the LF’s DM, thus revealing minor acid autohydrolysis consequently leading to minor NS production during the steam pretreatment. WCLB subjected to SC at 210°C (SC210) generated up to 2.7-fold bioaccessible glucan and xylan. SC and SE pretreatments showed potential for the deconstruction of WCLB (delignification, depolymerisation, decrystallization and deacetylation), enhancing its enzymatic hydrolysis. The concentrations of enzymatic inhibitors such as 2-furfuraldehyde and 5-(hydroxymethyl)furfural from LFSC210 were the highest (41 and 21 µg mL-1, respectively). This study shows that steam pretreatments in general and SC210 in particular are required for efficient bioconversion of WCLB. Yet, biotransformation through biochemical processes (e.g., anaerobic digestion) must be performed to assess the efficiency of these pretreatments. [less ▲]

Detailed reference viewed: 23 (6 ULg)
Full Text
See detailEt si nos déchets devenaient la source de nouveaux produits. Notion d'économie circulaire
Jacquet, Nicolas ULg; Istasse, Thibaut ULg; Berchem, Thomas ULg et al

Conference given outside the academic context (2015)

Notre objectif et nos recherches se concentrent sur l'utilisation des déchets agricoles et forestiers, les déchets végétaux et industriels et nos déchets ménagers pour produire une gamme de nouveaux ... [more ▼]

Notre objectif et nos recherches se concentrent sur l'utilisation des déchets agricoles et forestiers, les déchets végétaux et industriels et nos déchets ménagers pour produire une gamme de nouveaux produits, biocarburants ou molécules chimiques. [less ▲]

Detailed reference viewed: 21 (0 ULg)
Full Text
Peer Reviewed
See detailLes initiatives commerciales de bioraffinage en Région Wallonne: production de biocarburants et voies de valorisation connexes
Jacquet, Nicolas ULg; Desquay, Lucas ULg; Jadot, Bastien et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2015), 19(2), 197-203

Introduction Biorefining is progressively gaining interest in Wallonia as a complement to the conventional petrochemical industry. Biorefineries are categorized according to the nature of the raw ... [more ▼]

Introduction Biorefining is progressively gaining interest in Wallonia as a complement to the conventional petrochemical industry. Biorefineries are categorized according to the nature of the raw materials they treat (food or non-food) and the nature of their productions (energy and biofuels or biobased compounds). Literature Production of first-generation and second-generation biofuels (bioethanol and biodiesel) is described, as well as their parallel valorisation pathways. A description of the Belgian biobased industry is also provided. Conclusion Diversification of supply chains, as well as the need to promote a circular economy, becomes a priority for the development of biorefining in Wallonia. [less ▲]

Detailed reference viewed: 43 (10 ULg)
Full Text
Peer Reviewed
See detailApplication of Steam Explosion as Pretreatment on Lignocellulosic Material: A Review
Jacquet, Nicolas ULg; Maniet, Guillaume ULg; Vanderghem, Caroline ULg et al

in Industrial & Engineering Chemistry Research (2015), 54(10), 2593-2598

Steam explosion is a thermo-mechanicochemical pretreatment which allows the breakdown of lignocellulosic structural components by the action of heating, formation of organic acids during the process, and ... [more ▼]

Steam explosion is a thermo-mechanicochemical pretreatment which allows the breakdown of lignocellulosic structural components by the action of heating, formation of organic acids during the process, and shearing forces resulting in the expansion of the moisture. Two distinct stages compose the steam-explosion process: vapocracking and explosive decompression which include modification of the material components: hydrolysis of hemicellulosic components (mono- and oligosaccharides released), modification of the chemical structure of lignin, and modification of the cellulose crystallinity index, etc. These effects allow the opening of lignocellulosic structures and influence the enzymatic hydrolysis yield of the material. [less ▲]

Detailed reference viewed: 19 (9 ULg)
Full Text
Peer Reviewed
See detailOak barks as raw materials for the extraction of polyphenols for the chemical and pharmaceutical sectors: a regional case study
Dedrie, Maxime; Jacquet, Nicolas ULg; Bombeck, Pierre-Louis ULg et al

in Industrial Crops and Products (2015), 70

Despite their potential for chemical recycling, residues from forest harvesting and wood processing are mostly used for industrial applications with low added value (energy, paper pulp, panels). Bark of ... [more ▼]

Despite their potential for chemical recycling, residues from forest harvesting and wood processing are mostly used for industrial applications with low added value (energy, paper pulp, panels). Bark of both oak species, Quercus robur L. 1753, Quercus petraea (Matt.) Liebl. 1784 is a by-product from sawmill and pulp mill activities. Bark is mainly used as a fuel for the same wood plants. The aim of this study is to look at the feasibility of enhancing the value of this material through the extraction of bioactive molecules such as polyphenols (i.e. catechin, gallic and ellagic acids). First, the effect of industrial storage of logs and bark on their polyphenol content was explored. Then, referring to the selection of tan oaks in the past, the question of an optimum harvesting age is addressed in order to maximize the polyphenol content of the barks. In the end, molecular diversity of bark is examined through the identification of molecules of interest, using different chromatographic analyses. The results show an effect of the industrial context and an effect of the raw material age on the chemical properties of the bark. First investigations also highlight molecules of interest and the molecular diversity, which needs to be further explored. [less ▲]

Detailed reference viewed: 32 (9 ULg)
Full Text
Peer Reviewed
See detailMicrowave-assisted thermochemical and primary hydrolytic conversions of lignocellulosic resources: a review
Richel, Aurore ULg; Jacquet, Nicolas ULg

in Biomass Conversion and Biorefinery (2015), 5(1), 115-124

Faced with the inevitable depletion of fossil resources, agricultural productions have rapidly emerged as promising renewable alternatives. Particularly, the conversion of lignocellulosic materials has ... [more ▼]

Faced with the inevitable depletion of fossil resources, agricultural productions have rapidly emerged as promising renewable alternatives. Particularly, the conversion of lignocellulosic materials has nowadays opened new vistas for the production of energy, biofuels and chemicals. In this literature review, microwave technology is described as an original heating source either for the thermochemical conversions (at temperatures up to 400°C) of lignocellulose into biofuels or the pretreatment (below 400°C) and further hydrolysis of lignocellulose into bioethanol and other valuable chemicals. Advantages of microwave approaches include a commonly observed acceleration in reaction rate and improved selectivities and yields. [less ▲]

Detailed reference viewed: 52 (22 ULg)
Full Text
See detailSustainable Chemistry
Gillet, Sébastien ULg; Jacquet, Nicolas ULg; Richel, Aurore ULg

Learning material (2014)

1) Petrochemical and concept of biorefineries. 2) Biomass and biorefineries, 1st generation 3) Biomass and biorefineries, second generation 4) Green Chemistry and Green Engineering

Detailed reference viewed: 39 (14 ULg)
Full Text
See detailUse of 13C-NMR in structural elucidation of polysaccharides: case of locust bean gum
Gillet, Sébastien ULg; Aguedo, Mario ULg; Blecker, Christophe ULg et al

Poster (2014, November 25)

Locust bean gum (LBG) galactomannans are polysaccharides consisting of a β-(1→4) D-mannopyranosyl backbone substituted to varying degrees in α-(1→6) with single D-galactopyranosyl residues. This basic ... [more ▼]

Locust bean gum (LBG) galactomannans are polysaccharides consisting of a β-(1→4) D-mannopyranosyl backbone substituted to varying degrees in α-(1→6) with single D-galactopyranosyl residues. This basic structure is the same for all galactomannans (Fig. 2). However, when locust bean gum is extracted at different temperatures, the generated fractions exhibit different properties in aqueous solution (viscosity, viscoelasticity, gel formation, thermohydrolysis resistance, etc.). This means that there are differences within the fine structure of the polymers (although the basic structure is the same). Analysis of [13C]-NMR spectra of galactomannans, in combination with other techniques, can provide capital information about fine structural elucidation of the polymers. The method specifies the distribution of lateral galactosyls along the main chain of mannans. Two fractions extracted from locust bean gum at 25 and 80 °C (respectively GM25 and GM80) were comparatively studied by [13C]-NMR. Mannosyls/Galactosyls (M/G) ratios can be determined by considering the intensities of C-1 mannose and galactose signals in [13C]-NMR spectra. This method provides results relatively close to those obtained by GC-MS analysis. Spectra also showed that resonance from C4 of D-mannose residues were split, in evident dependence upon the nearest-neighbor probabilities (“diad frequencies”) of D-galactosyl groups along the mannan chains (Fig. 2). Diad frequencies were obtained by integrating C4(Man) peak areas. F11, F21/F12 and F22 gave respectively the di-, mono- or non-substituted mannose pairs proportions. High percentages of F11 and F22 therefore indicate a more non-homogeneous distribution of lateral galactosyls along the polysaccharide backbone as observed for GM80. The percentages of total lateral substituents obtained by C4(Man) peak analysis [F11 + (F21 or F12)/2] were fairly well correlated with M/G ratios. Splitting of the C-6 substituted D-mannose resonance provides, therefore the basis for determining the next-nearest-neighbor probabilities (triad frequencies) (Fig. 2). However, the spectrum is often not sufficiently resolved to accurately quantify and interpret the results. [less ▲]

Detailed reference viewed: 24 (7 ULg)
Full Text
See detailImpact of steam explosion treatment on chemical configuration of Tall Fescue lignin : structural elucidation using NMR spectroscopy
Maniet, Guillaume ULg; Jacquet, Nicolas ULg; Gillet, Sébastien ULg et al

Poster (2014, November 24)

In the economic and energy context of our society, it is universally recognized that alternatives to petrochemicals products must be found. To overcome this problem, renewable lignocellulosic biomass ... [more ▼]

In the economic and energy context of our society, it is universally recognized that alternatives to petrochemicals products must be found. To overcome this problem, renewable lignocellulosic biomass could be used to produce high value products. To achieve this objective, pretreatment processes are required to allow the breakdown of lignocellulosic structure and increase accessibility of the material. In this way, steam explosion is a thermo-mechano-chemical pretreatment which allows the opening of lignocellulosic material structural components and includes modifications of the physical properties of the material, hydrolysis of hemicellulosic components and modification of the chemical structure of lignin [1]. This study is focused on the impact of various steam explosion treatments on the chemical configuration of tall fescue lignin. NMR analyses perform on the Festuca L. pretreated samples show variations of links with treatment intensity. Observations show double phenomen :re-polymerization and depolymerization of the lignin structure during steam explosion process [2]. In parallel, HPSEC analyses show modifications in the molecular weight of the lignin obtained after the steam explosion treatment. [less ▲]

Detailed reference viewed: 18 (8 ULg)
Full Text
See detailINFLUENCE OF STEAM EXPLOSION ON THECRYSTALLINITY OF CELLULOSE FIBER
Jacquet, Nicolas ULg; Vanderghem, Caroline ULg; Danthine, Sabine ULg et al

Poster (2014, February 07)

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct ... [more ▼]

The aim of the present study is to compare the effect of different steam explosion treatments on crystallinity properties of a pure bleached cellulose. Steam explosion process is composed of two distinct stages: vapocracking and explosive decompression. The treatment intensities is determined by a severity factor, established by a correlation between temperature process and retention time. The results show that steam explosion treatment has an impact on the crystallinity properties of pure cellulose fiber. When the severity factor is below 5.2, an increase of the overall crystallinity of the samples is observed with the treatment intensities. For higher intensities, a significant thermal degradation of cellulose lead to an important change in substrate composition, which lead to a further decrease of cellulose crystallinity. [less ▲]

Detailed reference viewed: 49 (3 ULg)
Full Text
Peer Reviewed
See detailEnzymatic hydrolysis of softwood and hardwood regenerated celluloses
Jacquet, Nicolas ULg; Maniet, Guillaume ULg; Richel, Aurore ULg et al

in Current Chemical Biology (2014), 8(2), 103-108

Regenerated celluloses from Kraft wood pulps (from hardwoods and softwoods) were hydrolysed by mean of cellulase of Trichoderma reesei. Our results highlighted that a 75% hydrolysis yield was reached for ... [more ▼]

Regenerated celluloses from Kraft wood pulps (from hardwoods and softwoods) were hydrolysed by mean of cellulase of Trichoderma reesei. Our results highlighted that a 75% hydrolysis yield was reached for hardwood regenerated cellulose (HRC) and 90% for softwood regenerated cellulose (SRC). Crystallinity indices from X-Ray diffraction patterns were used to measure hydrolysis rate of crystalline and amorphous regions. Addition of β-glucosidase to the enzymatic complex of Trichoderma reesei was confirmed to enhance yields of hydrolysis. [less ▲]

Detailed reference viewed: 51 (13 ULg)
Full Text
Peer Reviewed
See detailCan Lignin Wastes Originating From Cellulosic Ethanol Biorefineries Act as Radical Scavenging Agents?
Vanderghem, Caroline ULg; Jacquet, Nicolas ULg; Richel, Aurore ULg

in Australian Journal of Chemistry (2014), 67

Lignin is a co-product from the biorefinery and paper industry. Its non-energetic valorization remains a field of extensive R&D developments. In this perspective, this study is undertaken to evaluate the ... [more ▼]

Lignin is a co-product from the biorefinery and paper industry. Its non-energetic valorization remains a field of extensive R&D developments. In this perspective, this study is undertaken to evaluate the radical scavenging ability of some herbaceous lignins. These lignins, extracted from Miscanthus (Miscanthus x giganteus) or Switchgrass (Panicum Virgatum L.), are selected as benchmarks for this study as a function of their chemical structure and average molecular weight. These technical lignins, side-products in the bioethanol production process, are found to display a moderate antioxidant activity as evaluated by the DPPH (1,1-diphenyl-2-picrylhydrazil) free radical scavenging test system. A correlation between the radical scavenging properties and the molecular features is proposed and discussed. Infrared spectroscopy is evaluated as a straightforward qualitative prediction tool for the radical scavenging capacity. [less ▲]

Detailed reference viewed: 72 (34 ULg)
See detailLignin as a raw material for industrial materials applications
Richel, Aurore ULg; Vanderghem, Caroline ULg; Jacquet, Nicolas ULg et al

Poster (2014)

Native lignin is an abundant biopolymer on earth and represents 15-30% by weight of the lignocellulosic biomass. Lignin is a heterogeneous cross-linked polymer composed of phenylpropane units (guaiacyl ... [more ▼]

Native lignin is an abundant biopolymer on earth and represents 15-30% by weight of the lignocellulosic biomass. Lignin is a heterogeneous cross-linked polymer composed of phenylpropane units (guaiacyl, syringyl or p-hydroxyphenyl) linked together by a panel of specific ether or carbon-carbon bonds.[1] Nowadays, large amounts of lignins and lignin-based wastes are available and originate either from the pulp and paper manufacturing or from the production of bioethanol from lignocellulose. [2] Typically, these lignins are dedicated to energetic purposes by combustion. In recent years however, novel axes for high added value applications have emerged and concern, notably, the use of lignin as performance products (e.g. polymer additives, binders) or specialty chemicals (e.g. surface-active agents) for materials applications.[3] Herein, several applications of lignin in materials sciences with industrial issues are presented. A correlation is established between the extraction processes from lignocellulosic materials and the chemical structure and physico-chemical properties of lignins.[4] Our research group has also developed new methodologies for the extraction of highly pure lignins from several starting materials, including food wastes, herbaceous raw materials and wood biomass. These methodologies include microwave-assisted extraction and two-step conventional pretreatment involving steam explosion. These methodologies are described in this presentation. [less ▲]

Detailed reference viewed: 95 (19 ULg)
Peer Reviewed
See detailLignin as a raw material for industrial materials applications
Richel, Aurore ULg; Vanderghem, Caroline ULg; Jacquet, Nicolas ULg et al

Poster (2013, October)

Native lignin is an abundant biopolymer on earth and represents 15-30% by weight of the lignocellulosic biomass. Lignin is a heterogeneous cross-linked polymer composed of phenylpropane units (guaiacyl ... [more ▼]

Native lignin is an abundant biopolymer on earth and represents 15-30% by weight of the lignocellulosic biomass. Lignin is a heterogeneous cross-linked polymer composed of phenylpropane units (guaiacyl, syringyl or p-hydroxyphenyl) linked together by a panel of specific ether or carbon-carbon bonds.[1] Nowadays, large amounts of lignins and lignin-based wastes are available and originate either from the pulp and paper manufacturing or from the production of bioethanol from lignocellulose. [2] Typically, these lignins are dedicated to energetic purposes by combustion. In recent years however, novel axes for high added value applications have emerged and concern, notably, the use of lignin as performance products (e.g. polymer additives, binders) or specialty chemicals (e.g. surface-active agents) for materials applications.[3] Herein, several applications of lignin in materials sciences with industrial issues are presented. A correlation is established between the extraction processes from lignocellulosic materials and the chemical structure and physico-chemical properties of lignins.[4] Our research group has also developed new methodologies for the extraction of highly pure lignins from several starting materials, including food wastes, herbaceous raw materials and wood biomass. These methodologies include microwave-assisted extraction and two-step conventional pretreatment involving steam explosion. These methodologies are described in this presentation. [less ▲]

Detailed reference viewed: 49 (13 ULg)
Full Text
Peer Reviewed
See detailThe swelling behaviour of wheat starch granules during isothermal and non-isothermal treatments
Malumba Kamba, Paul ULg; Jacquet, Nicolas ULg; Delimme, Guy ULg et al

in Journal of Food Engineering (2013), 114(2), 199-206

The size of wheat starch granules was measured during isothermal and non-isothermal treatments and fitted using mathematical models in order to elucidate the time–temperatures dependence of the swelling ... [more ▼]

The size of wheat starch granules was measured during isothermal and non-isothermal treatments and fitted using mathematical models in order to elucidate the time–temperatures dependence of the swelling phenomenon and to improve our understanding of the mechanism followed by granules during gelatinization. Upon the onset temperature of gelatinization, starch granules size increase rapidly and tend to reach equilibrium values that depend on the temperature and heating rate applied. The most accurate fitting of granule size observed overall isothermal treatments was obtained with the third-order kinetic and the Weibull empirical models. The activation energy of swelling calculated for isothermal treatment varied between 41 and 318 kJ mol 1, depending on the mathematical model considered. Therefore, without a consensus on the mechanism and order of reaction followed during gelatinization, the meaningful of kinetic parameters calculated using mathematical models seems highly questionable. During non-isothermal treatments at lower heating rate, it seems like a limitation of the swelling capacity of granules was induced. This phenomenon was attributed to restructuration occurred inside of granules. So, forecasting the swelling behaviour of starch granules during non-isothermal treatment has to consider both the time–temperature and the heating rate applied. [less ▲]

Detailed reference viewed: 58 (15 ULg)
Full Text
Peer Reviewed
See detailInfluence of Homogenization Treatment on Physicochemical Properties and Enzymatic Hydrolysis Rate of Pure 5 Cellulose Fibers
Jacquet, Nicolas ULg; Vanderghem, Caroline ULg; Danthine, Sabine ULg et al

in Applied Biochemistry and Biotechnology (2013), 4

The aim of this study is to compare the effect of different homogenization treat- 12 ments on the physicochemical properties and the hydrolysis rate of a pure bleached 13 cellulose. Results obtained show ... [more ▼]

The aim of this study is to compare the effect of different homogenization treat- 12 ments on the physicochemical properties and the hydrolysis rate of a pure bleached 13 cellulose. Results obtained show that homogenization treatments improve the enzymatic 14 hydrolysis rate of the cellulose fibers by 25 to 100 %, depending of the homogenization 15 treatment applied. Characterization of the samples showed also that homogenization had an 16 impact on some physicochemical properties of the cellulose. For moderate treatment inten- 17 sities (pressure below 500 b and degree of homogenization below 25), an increase of water 18 retention values (WRV) that correlated to the increase of the hydrolysis rate was highlighted. 19 Result also showed that the overall crystallinity of the cellulose properties appeared not to be 20 impacted by the homogenization treatment. For higher treatment intensities, homogenized 21 cellulose samples developed a stable tridimentional network that contributes to decrease 22 cellulase mobility and slowdown the hydrolysis process. [less ▲]

Detailed reference viewed: 72 (35 ULg)