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Your search keyword '"Lopes Ferreira, Nicolas"' showing total 3 results
Start Over Author "Lopes Ferreira, Nicolas" Topic enzymatic hydrolysis
3 results on '"Lopes Ferreira, Nicolas"'

1. Optimization of a synthetic mixture composed of major Trichoderma reesei enzymes for the hydrolysis of steam-exploded wheat straw

Author

Billard Hélène, Faraj Abdelaziz, Lopes Ferreira Nicolas, Menir Sandra, and Heiss-Blanquet Senta

Subjects
Trichoderma reesei, cellulases, xylanase, wheat straw, enzymatic hydrolysis, experimental design, Fuel, TP315-360, Biotechnology, TP248.13-248.65
Abstract

Abstract Background An efficient hydrolysis of lignocellulosic substrates to soluble sugars for biofuel production necessitates the interplay and synergistic interaction of multiple enzymes. An optimized enzyme mixture is crucial for reduced cost of the enzymatic hydrolysis step in a bioethanol production process and its composition will depend on the substrate and type of pretreatment used. In the present study, an experimental design was used to determine the optimal composition of a Trichoderma reesei enzyme mixture, comprising the main cellulase and hemicellulase activities, for the hydrolysis of steam-exploded wheat straw. Methods Six enzymes, CBH1 (Cel7a), CBH2 (Cel6a), EG1 (Cel7b), EG2 (Cel5a), as well as the xyloglucanase Cel74a and the xylanase XYN1 (Xyl11a) were purified from a T. reesei culture under lactose/xylose-induced conditions. Sugar release was followed in milliliter-scale hydrolysis assays for 48 hours and the influence of the mixture on initial conversion rates and final yields is assessed. Results The developed model could show that both responses were strongly correlated. Model predictions suggest that optimal hydrolysis yields can be obtained over a wide range of CBH1 to CBH2 ratios, but necessitates a high proportion of EG1 (13% to 25%) which cannot be replaced by EG2. Whereas 5% to 10% of the latter enzyme and a xylanase content above 6% are required for highest yields, these enzymes are predicted to be less important in the initial stage of hydrolysis. Conclusions The developed model could reliably predict hydrolysis yields of enzyme mixtures in the studied domain and highlighted the importance of the respective enzyme components in both the initial and the final hydrolysis phase of steam-exploded wheat straw.

Published
2012
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2. Mechanistic modeling of enzymatic hydrolysis of cellulose integrating substrate morphology and cocktail composition

Author

Huron, Maïté, Hudebine, Damien, Lopes Ferreira, Nicolas, Lachenal, Dominique, IFP Energies nouvelles (IFPEN), Inst National Polytechnique de Grenoble (INPG), and Institut National Polytechnique de Grenoble (INPG)

Subjects
Substrate morphology, Enzymatic hydrolysis, Modeling, [CHIM]Chemical Sciences, [CHIM.CATA]Chemical Sciences/Catalysis, Cellulose, Enzymes
Abstract

International audience; A complete mechanistic model of enzymatic hydrolysis taking into account the morphology of the cellulosic particles and its evolution with time was developed. The individual behavior of the main enzymes involved in the reaction (cellobiohydrolases, endoglucanases and β-glucosidases), as well as synergy effects, were also included. A large panel of experimental tests was done to fit and validate the model. This database included different enzymes mixtures and operating conditions and allowed to determine and compare with accuracy the adsorption and kinetic parameters of the different enzymes. Model predictions on short hydrolysis times were very satisfactory. On longer times, a deactivation constant was added to represent the hydrolysis slowdown. The model also allowed to predict the impact of enzymes ratios and of initial substrate parameters (chain length distribution, polymerization degree) on hydrolysis, and to follow the evolution of these parameters with time. This model revealed general trends on the impact of cellulose morphology on hydrolysis. It is a useful tool to better understand the mechanisms involved in enzymatic hydrolysis of cellulose and to determine optimal cellulolytic cocktails for process design.

Published
2016

3. Kinetic modeling of the enzymatic hydrolysis of cellulose integrating the evolution of the substrate morphology

Author

Huron, Maïté, Hudebine, Damien, Lopes-Ferreira, Nicolas, Lachenal, Dominique, IFP Energies nouvelles (IFPEN), Inst National Polytechnique de Grenoble (INPG), Institut National Polytechnique de Grenoble (INPG), and Bertrand, Françoise

Subjects
Enzymatic Hydrolysis, Kinetics, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Modeling, [INFO.INFO-MO] Computer Science [cs]/Modeling and Simulation, Biomass, [CHIM.ORGA] Chemical Sciences/Organic chemistry, 7. Clean energy, Lignocellulose, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation
Abstract

The enzymatic hydrolysis is one of the main bottlenecks in the process of lignocellulose bioconversion to produce ethanol. In order to optimize the saccharification step and reduce the enzyme loading, a model must be developed to predict the behavior of the lignocellulose during the enzymatic attack. The morphology of the cellulosic substrate and its evolution during the hydrolysis step is strongly linked to the global performances of the enzymatic cocktail and has to be taken into account. To improve the accuracy of the prediction, the model should also distinguish the action of the different types of enzymes which are present in the cocktail. In the model proposed in this article, the morphology of the cellulosic substrate, the specific action of each enzyme, the synergy between the enzymes and the product inhibitions are taken into account. This model will be next extended to real pretreated lignocellulosic substrates (containing lignin)., Proceedings of the 21st European Biomass Conference and Exhibition, 3-7 June 2013, Copenhagen, Denmark, pp. 1369-1377

Published
2013

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