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Thesis presentation

  1. 1. Effect of Different Pretreatment Methods in Combination with the Organosolv Delignification Process and Enzymatic Hydrolysability of Three Feedstocks in Correlation with Lignin Structure Yakindra Prasad Timilsena Examination Committee  Prof. Sudip K. Rakshit (Chairperson)  Prof. Nicolas Brosse (Co-advisor)  Prof. Athapol Noomhorm  Dr. Anil Kumar Anal
  2. 2. Overview of Presentation1 Introduction2 Review of Literatures3 Materials and Methods4 Results and Discussions5 Conclusions 2
  3. 3. IntroductionLignocellulosics→ Plentiful supply & Renewable resources→ Comparatively low cost→ No competition with food and feed production→ Environmentally benign 3
  4. 4. Problem Statement Introduction Background ObjectivesPotential sources• Dedicated crops• Invasive plants• Agro-industrial waste 4
  5. 5. Problem statement Introduction Background Objectives Lignocellulosic Conversion Process • Direct combustion • Biogas (Gasification, Anaerobic digestion) • Biofuels (Bioethanol, biomethanol, Fischer- Tropsch (FT) diesel, biobutanol, Biohydrogen) Conversion to Holocellulose monomeric sugarsLignocellulosics Lignin Conversion to renewable Adhesive, biodegradable fuel, chemicals or polymers, bioantioxidant, food 5
  6. 6. Lignocellulosics Lignocellulosics Application 6
  7. 7. Pretreatment Problem statement Background Objectives  Important processing step in biomass conversion  alter the structure of the biomass  break the lignin seal  disrupt the crystalline structure of cellulose (Adapted from Hsu et al., 1980). 7
  8. 8. Background Introduction ObjectivesMethods of pretreatment Methods Combinative pretreatment 8
  9. 9. Problem Statement Problem statement Background Objectives• Selection of feedstock (Composition, growthrequirement, productivity, land/watercompetition with food or fodder, biomassnature and ease of delignication and pulp yield)• Selection of pretreatment method (long list of optimized methods, difficult to choose) 9
  10. 10. Problem Statement Rationale Background Objectives• Molecular structure of constituentpolymers, especially lignin 10
  11. 11. Background Objectives Objectives Objective 1 Objective 2 Objective 3To compare the To characterize and describe To evaluate thedelignification Typha lignin and effect ofability of different establish aromaticprehydrolysis correlation compounds inmethods and to between lignin organosolv structure (S/G delignificationassess the ratio) and ability ofeffectiveness of delignification Miscanthuspretreatment ability 11
  12. 12. Literature ReviewS.N. Feed- Pretreatment Findings Author &Year stock method1. Aspen Autohydrolysis & - Positive effect of aromatics in Wayman & solvent extraction delignification Lora, 19782. Bagasse Presoaking, - Better effect of prehydrolysis Patel & prehydrolysis+ Varshney, 1989 organosolv delignification3. MxG DAP + Ethanol - Presoaking has better effect Brosse et al., organosolv process on xylan recovery, 2009 delignification and enzymatic digestibility4. MxG Lignin - Description of two kinds of El Hage et al., characterization lignin from MxG 20095. MxG Autohydrolysis + -Autohydrolysis enhanced the El Hage et al., OS delignification 2010 - Positive effect of 2-naphthol 12
  13. 13. MATERIALS & METHODS Pressure Guaze Reactor Heater Temp. Controller 13
  14. 14. Raw Materials Raw Materials Prehydrolysis Organosolv Process Enzymatic Hydrolysis Lignin Separation & Characterizati Miscanthus x Giganteus energy dedicated crop Palm oil industry Perennial grass agricultural by-product Non invasive low costRequires no nitrogen / herbicide 6 million tons /year in Malaysia Produces 20-25 tons /ha/year Typha capensis invasive grass fast growing , highly prolific (50-60 ton/ha/year)
  15. 15. OBJECTIVE 1To compare the delignification ability of differentprehydrolysis methods and to assess theeffectiveness of pretreatment • Pulp yield • EOL yield • KL content of the pulp • Total reducing sugar and glucose yield 15
  16. 16. Raw MaterialsMaterials and Methods Prehydrolysis Organosolv Process Enzymatic Hydrolysis Lignin Separation & Characterizati 16
  17. 17. Raw Materials Materials and Methods Prehydrolysis Organosolv Process Enzymatic HydrolysisSecond step: Organosolv Delignification Lignin Separation & Characterizati 17
  18. 18. Composition Results and Discussions Prehydrolysis Combinative pretreatment Enzymatic hydrolysability1. Composition of untreated biomass Lignin Characterization 100Content (% extractive free dry wt basis) 90 23.1 20.4 25.9 Lignin (%) 80 Hemicellulose (%) 70 Cellulose (%) 60 26.7 28.5 38.4 50 40 30 47.4 48.4 20 41.2 10 0 MxG EFB Typha Feedstock • Holocellulose extraction by sulphite Glucans and xylans: 75-80% delignification method • Cellulose extraction by alkaline method Lignin: 20-25% (TAPPI) • Lignin by difference Composition almost similar for all biomasses 18
  19. 19. Composition Composition of Prehydrolysis untreated biomass Combinative pretreatment Enzymatic hydrolysability Lignin CharacterizationComposition after prehydrolysis  Xylans hydrolysed and removed in large amount (Typha>EFB>MxG)  Partial lignin removal  Pulp rich in cellulose 19
  20. 20. Composition Results and Discussions Prehydrolysis Combinative pretreatment Enzymatic hydrolysability Lignin Characterization Lignin substantially removed Higher mass loss 20
  21. 21. Composition Results and Discussions Prehydrolysis Combinative pretreatment Enzymatic hydrolysability EOL & KL Content of the pulp after Lignin Characterization organosolv delignification EOL 18 KLPercentage (dry biomass basis) 20.0 17 16 16 18.0 16 14 16.0 13 12 14.0 12 12 11 12 10 12.0 8 10.0 8 8 8 7 1 6 7 8.0 6 5 6 6 5 5 5 5 6 6 6.0 4.0 2 2.0 1 1 0.0 Miscanthus EFB Typha Treatments  Prehydrolysis step enhanced the subsequent delignification (destruction of lignin seal, easier delignification)  DAP, SP & EP: not very efficient (significant delignification of EFB in DAP)  Naphthol : positive effect for MxG and EFB; no effect in Typha  Typha has different behaviour; easier to delignify even with single step pretreatment. 21
  22. 22. Composition Results and Discussions Prehydrolysis Combinative pretreatmentMxG: Yield of total reducing sugars and glucose Enzymatic hydrolysability Lignin Characterization 70 61 Reducing sugar 58 60 Glucose 52 50 49 50 45 44 Sugar content (%) 39 40 38 33 29 30 30 28 25 24 20 15 11 10 6 7 3 0 RM_M DAP AHN SP OS DAP+OS AH + OS EP + OS AHN + OS SP+OS Treatments  low hydrolysability after prehydrolysis  low hydrolysability after organosolv alone (performed at low severity, low conc. of sulfuric acid, low temperature..)  hydrolysability enhanced after combinative treatment. Organosolv is necessary because it removes a large part of lignin and make cellulose more accessible 22
  23. 23. Composition Results and Discussions Prehydrolysis Combinative pretreatmentEFB: Yield of total reducing sugars and glucose Enzymatic hydrolysability Lignin Characterization 70 64 Reducing sugar 61 60 Glucose 54 50 49 50 44 Sugar content (%) 39 40 34 33 32 32 29 30 27 26 24 22 22 19 20 10 10 5 0 RM_E DAP AHN SP OS DAP+OS AH + OS EP + OS AHN + OS SP+OS Treatments  good correlation was observed between Lignin content & hydrolysability  Dilute acid prehydrolysis+Organosolv process showed best result. 23
  24. 24. Composition Results and Discussions Prehydrolysis Combinative pretreatmentTypha: Yield of total reducing sugars and glucose Enzymatic hydrolysability Lignin Characterization 70 Reducing sugar 60 61 59 60 Glucose 57 58 53 50 46 45 43 42 43 43 41 Sugar content (%) 39 39 40 36 35 34 34 29 30 27 21 20 13 10 6 0  Typha demonstrated different behaviour Treatments  Good hydrolysability after the prehydrolysis even if the KL content in the pulp are high  Reactivity toward enzyme only slightly improved after OS  Typha is easier to delignify, one step process showed tantamount effect  No effect of naphthol on delignification ability 24
  25. 25. OBJECTIVE 2To characterize and describe Typha lignin andestablish correlation between lignin structure (S/Gratio) and delignification ability• FTIR • Major peak assignment &• NMR description• GPC • Relative amount of constituent moieties (S/G ratio) • Mn, Mw & PI 25
  26. 26. Raw Materials Materials and Methods Prehydrolysis Organosolv Process Enzymatic Hydrolysis Lignin Separation & CharacterizatiLignin Isolation 26
  27. 27. Raw Materials Materials and Methods Prehydrolysis Organosolv Process Enzymatic Hydrolysis Lignin Separation & CharacterizatiLignin characterization• Two fractions of lignin analysed (CEL & EOL)• Spectroscopic methods (FTIR & NMR)• Chromatographic method (GPC) 27
  28. 28. Composition Results and Discussions Prehydrolysis Combinative pretreatment Enzymatic hydrolysability Lignin CharacterizationLignin polymer • Lignin is a complex natural polymer comprised of p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) units • (S/G) ratio- important characteristic (because G has high tendency to recondensed >> delignification more difficult) H G S Adapted from Wershaw, 2004 28
  29. 29. Composition Results and Discussions Prehydrolysis Combinative pretreatmentFTIR spectra of Typha CEL Enzymatic hydrolysability Lignin Characterization 70,5 65 - 1515.9 G+S - 1329.5 S 60 2065,0 - 1240 G 55 3854,3 - 1166.8 typical of 50 3821,4 HGS lignin - 1125.9S 45 2341,5 - 1033.8 G 2360,0 40 - 834.7 G+S 35%T 30 25 1166.8 20 834,7 668,3 15 1369,4 605,6 527,5 10 1125,9 2933,8 1240,1 1729,9 5 3412,1 1329,5 1033,8 1515,9 1604,6 1457,3 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400,0 Wavelength (cm-1)  H-G-S lignin (usual for herbaceous crop) 29
  30. 30. Composition Results and Discussions Prehydrolysis Combinative pretreatmentFTIR Peak assignment for Typha CEL Enzymatic hydrolysability Lignin Characterization - 1515.9 G+S - 1329.5 S - 1240 G - 1166.8 typical of HGS lignin - 1125.9S - 1033.8 G - 834.7 G+S 30
  31. 31. Composition Results and Discussions Prehydrolysis Combinative pretreatmentNMR spectra of Typha CEL Enzymatic hydrolysability Lignin Characterization  Presence of residual sugars (peaks at 95-100ppm & 70-75ppm)  High Acetylation content: 0.44 acetate group/aryl (0.06 for Miscanthus)  Low paracoumaryl content : 0.01 PC group/aryl (0.1 for MxG)  S/G/H= 55/15/30  Very high S/G ratio (3.7)  High S/G ratio support the easier delignification (Del Río et al., 2005) 31
  32. 32. Composition Results and Discussions Prehydrolysis Combinative pretreatmentNMR spectra of Typha CEL (A) & EOL (B) Enzymatic hydrolysability Lignin Characterization Comparison Typha EOL and CEL  EOL non sugar (peaks at 95- 100ppm + 70-75ppm)  propyl side chain shows deconstruction of -O-4 linkage (60-90ppm)  Acetate extensively 153 147 hydrolysed during organosolv hydrolysis  In EOL, S etherified (153ppm is very low but S non etherified (147ppm) very high extensive depolymerization through aryl ether bond cleavage. 32
  33. 33. Comparison of lignin from three feedstocks 33
  34. 34. Composition Results and Discussions Prehydrolysis Combinative pretreatmentSEC analysis of Typha CEL and EOL Enzymatic hydrolysability Lignin Characterization Lignin Mw Mn PI=Mw/Mn EOL 4567 2877 1.59 CEL 9268 4109 2.26 • Higher molecular weight and polydispersity index of CEL • Cleavage of aryl ether bonds & formation of smaller fragments during organosolv process • Agreed with NMR results 34
  35. 35. Composition Results and Discussions Prehydrolysis Combinative pretreatmentSEC analysis of Typha CEL and EOL Enzymatic hydrolysability Lignin Characterization Lignin Mw Mn PI=Mw/Mn CEL 9268 4109 2.26 • Higher molecular weight and polydispersity index of CEL • Cleavage of aryl ether bonds & formation of smaller fragments during organosolv process • Agreed with NMR results 35
  36. 36. OBJECTIVE 3To evaluate the effect of aromatic compounds inorganosolv delignification ability of Miscanthus 2-naphthol• p- cresol• o-cresol • EOL yield • Klason lignin• hydroquinone content of the pulp • Acid soluble lignin• dihydroxyanthraquinone 36
  37. 37. Raw MaterialsMaterials and Methods Prehydrolysis Organosolv Process Enzymatic Hydrolysis Lignin Separation & Characterizati 10 g ODW Miscanthus Mixed with 0.4 g aromatics and soaked in 100 mL acetone overnight Acetone evaporation by air drying Autohydrolysis (1500C, 8h, S/L=1:9)OS delignification (1700C, 1h, SA=0.5%, S/L=1:8) Filtration Liquid EOL phase KL Pulp 37
  38. 38. Effect of aromatics on delignification 30 EOL yield (% ) KL (%) 25Yield (%) 20 15 10 5 13.3 14.9 20.8 5.9 16.8 7.3 23.4 3.8 17.8 8.3 22 4.8 0 Control Naphthol o-Cresol p-Cresol Hydroquinone DHAq Treatments 38
  39. 39. Effect of aromatics on delignification 39
  40. 40. Scavenging action of aromatics path 1 occurs if the blueFor feedstocks with the fragment is a G unitlow G content, path 0 is (more reactive). >>favoured Path 0 important for MxG 40
  41. 41. Conclusions• Despite a very similar chemical composition, three biomasses demonstrated different behavior during pretreatment.• Typha was easier to delignify; one step pretreatment (prehydrolysis or delignification) process was sufficient to break the lignin seal and release the sugars for enzymatic action. The combinative pretreatment not necessary• The first step of pretreatment (i. e. prehydrolysis) significantly enhance the efficacy of the second step of delignification of MxG and EFB and enzymatic hydrolysability also. DAP plus OS pretreatment resulted into best results for EFB. Autohydrolysis in presence of naphthol plus OS pretreatment (AHN) is best for MxG.• The treatment of biomass with a catalytic amount of aromatic compounds like 2-naphthol during autohydrolysis exhibited a substantial effect on both MxG and EFB delignification as well as on enzymatic hydrolysability. 41
  42. 42. Conclusions• Typha lignin is of H-G-S nature as usual to other herbaceous plants but with high S/G ratio suggesting its easier delignification• Addition of catalytic amount of aromatic scavengers enhanced delignification substantially (2-naphthol, p-cresol and dihydroxyanthraquinone with tantamount effect)• a better knowledge of biomass at the molecular level allow a better optimization of pretreatment 42
  43. 43. Recommendations• Obnoxious Typha an interesting guinea-pig for tropical biorefinery sector. Additional research for its valorization essential.• Experimentation on effect of additional aromatic scavengers in various feedstocks essential. 43
  44. 44. INDEBTED TO SDCC / AIT – France Network 44
  45. 45. « Think global, act local » GREEN PROCESSGreen EnergyGreen WorldTHANKS FOR YOUR ATTENTION!!!

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