Post Doctorate Proposal 2017

School: CentraleSupélec

Laboratory: LGPM Web site: www.lgpm.ecp.fr

Name of the supervisor: Patrick PERRE Email: patrick.perre@centralesupelec.fr

Expected duration (< 24 M): 24 months Location: Gif-sur-Yvette (20 km south of Paris)

Title: Multiscale modeling of the enzymatic attack of lignocellulosic biomass for biofuel production

Scientific field: Applied mathematics, biophysics, biochemistry

Key words: Second generation biofuel, volume averaging, high performance computation

Details for the subject:

Background,Context:

Themainobjectiveofthepretreatmentofbiomass,akeystepintheproductionofsecond-generationbiofuel,istoincreasetheavailabilityofpolysaccharidesforenzymestoattack(SunandCheng2002;Alviraetal.2010;Pingalietal.2010).Toobtainarelevantpretreatment,theoperatingconditionsoftheprocessshouldinsureagoodcompromisebetweentheinitialcharacteristicsofthebiomass,thekineticsofitsdegradationduringthecookingphase(acidichydrolysis),andtheefficiencyofthesubsequentenzymatictreatment.Followingaprototypedevelopedtomeasureviscoelasticpropertiesofwoodundersaturatedconditionsupto130°C(Placetetal.,2008),our laboratory(LGPM)developedanoriginaldeviceabletocontinuouslymeasuretheviscoelasticpropertiesof lignocellulosicbiomassduringacidiccookingupto190°C (Mokdadetal.2017).Additionalworksareinprogressinourteamtoobjectivelyrelytheevolutionofviscoelasticpropertiesduringhydrolysistochemicalmodifications(productionofsaccharidesandpolysaccharidesaswellastheproductionofinhibitorstoenzymaticattacksuchasfurfural).Asexpected,aceticacidandC-5sugarsaremainlyproducedduringacidiccooking,withasmallamountofC-6sugarsandpotentialinhibitorsforenzymaticattacksuchasfurfural.Thenextstepistofollowtheenzymaticattackofsampleswithvariouscookingconditionsofwell-knownpre-treatment. This experimental work is part of a PhD project. The present post-doctoral position intends toconductacomprehensivemodellingworkabletopredictthekineticsofenzymaticattackasafunctionofthemolecularalterationduringpretreatment.

Researchsubject,workplan:

Theprojectaimsatdevelopingamultiscaleandmulitphysicsmodellingapproachof theenzymaticattackofpre-treatedlignocellulosicbiomass.Themodeltobedevelopedshouldbecloseenoughtotherealstructureofthesecondarycellwall(Fig.1)tohaveapredictivepotential.Inparticular,weexpectthemodeltobeabletoaccount for the size of particles and to the alteration of the macromolecular structure due to the pre-treatment,includinginhibitors.

Theproblemisbynaturemultiscale(exchangesbetweentheliquidandsolidphases,effectoftheparticlesize,thicknessofthecellwallandheterogeneousstructureofthecellwall).Asseveralphysicalphenomenaco-existduring enzymatic attack (mobility of enzymes in a heterogeneous medium, enzymatic activity of cellulose,diffusionofsugars,time-evolutionofcell-wallmorphology),theproblemisthereforealsomultiphysics.

Fig.1–Molecularstructureofthesecondarywallofplants(afterLanganetal.GreenChemistry,2013)

Forthischallengingprojectinadomainofgreatinterestregardingsustainabledevelopment,wearelookingfora talented and motivated candidate with excellent skills in modelling (formulation aspects) and simulation(developmentofcustomcomputationalcodesorgoodcommandofopen-sourcemultiphysicssoftwares).Thepotential candidate should also have good skills in communication andmust be prone to teamwork, as theprojectshouldadvanceincloserelationwithscientistsinchargeoftheexperimentalwork.The selected candidatewill evolve in aworld-class teamwith balanced skills and extensive facilities in bothexperimentandHPC(seereferencesbelow).

References:

1. Alvira, P., Tomás-Pejó, E., Ballesteros, M., and Negro, M.J., 2010 - Pretreatment technologies for an efficientbioethanolproductionprocessbasedonenzymatichydrolysis:areview,BioresourceTechnol.101:4851-4861.

2. CarrE.,Turner I.,PerréP.,2013 -Adual-scalemodelingapproach fordryinghygroscopicporousmedia,MultiscaleModeling&Simulation,11:362-384.

3. Carr E., Perré P., Turner I., 2016 - The extended distributedmicrostructuremodel for gradient-driven transport: Atwo-scalemodelforbypassingeffectiveparameters,J.ComputationalPhysics,327:810-829.

4. CavagnolS.,SanzE.,NastollW.,Roesler J.F.,ZymlaV.,PerréP.,2013- Inverseanalysisofwoodpyrolysiswith longresidencetimesinthetemperaturerange210to290°C:selectionofmulti-stepkineticsmodelsbasedonmasslossresidues,ThermochimicaActa,574:1-9.

5. Mokdad S. A., Casalinho J., Almeida G., Perré P. 2017 - Assessment of biomass alterations during hydrothermalpretreatmentbyin-situdynamicmechanicalanalysis,BiomassandBioenergy,underreview.

6. PerréP.,2010-Multiscalemodellingofdryingasapowerfulextensionofthemacroscopicapproach:applicationtosolidwoodandbiomassprocessing,DryingTechnology,28:944-959.

7. Perré P., RémondR., Turner I.W., 2013 - A comprehensive dual-scalewood torrefactionmodel: application to theanalysisofthermalrun-awayinindustrialheattreatmentprocesses,Int.J.HeatMassTransfer,64:838-849.

8. Pingali,S.V.,Urban,V.S.,Heller,W.T.,McGaughey,J.,O’Neill,H.,Foston,M.,Evans,B.R.,2010-Breakdownofcellwallnanostructureindiluteacidpretreatedbiomass.Biomacromolecules,11,2329-2335.

9. Placet V., Passard J., Perré P., 2008 - Viscoelastic properties of wood across the grain measured under water-saturatedconditionsupto135°C:evidenceofthermaldegradation,J.Mater.Sci.,43:3210–3217.

10. Sun, Y., and Cheng, J., 2002 - Hydrolysis of lignocellulosicmaterials for ethanol production: a review.Bioresourcetechnology,83(1),1-11.