Characterizing Lignocellulosics from Miscanthus Cellulose - Lignin Poulomi Sannigrahi A.J. Ragauskas School of Chemistry and Biochemistry Georgia Institute of Technology
Agro-energy gy feedstock: Miscanthus Perennial crop Grows to 11-14 ft in height/year High biomass yields C4 grass with high rate of carbon fixation 14 17 tons/acre (up to 27 tons/acre in trials) Crop stands survive 25-30 years without significant loss in biomass yields Presently used in Europe for power and heat generation 2
Moisture and Ash content Moisture content of air dried miscanthus sawdust (6 mm) 4.6% Ash content Measured ed by ramped heating to 525 C in a muffle furnace 2.2% 2% Higher than Loblolly pine (0.2 %) & sweetgum (0.8 %) 3
Elemental analysis Measured on 0.05 mm ground samples using elemental micro analyzer 60.0 50.0 40.0 Miscanthus Sweetgum Loblolly Pine Wt.% 30.0 20.0 10.00 4 0.0 C H O N
Inorganic elements Analyzed in 6 mm ground samples Acid digestion followed by ICP-emission spectroscopy Coulometric method for total halogen (Cl+Br+I) 5
Inorganic elements 6 Co ontent (mg/kg) o.d. weight 380.0 360.0 340.00 320.0 300.0 280.0 260.0 240.0 220.0 200.00 180.0 160.0 140.0 120.0 100.0 80.0 60.00 40.0 20.0 0.0 Miscanthus Sweetgum L.Pine Ba Cu Fe Na P Si
Inorganic elements 2000.0 1750.0 Conte ent (mg/kg ove en dried weig ght) 1500.0 1250.0 1000.0 750.00 500.0 Miscanthus Sweetgum L.Pine 250.0 7 0.0 Ca K Mg S Mn Cl+Br+I
Acid soluble and insoluble lignin Klason lignin Acid idinsoluble lbl lignin i isolated ltdusing NREL methods thd Extractive free (40 mesh) sample hydrolyzed using 72 %HSO % H 2 SO 4 Acid soluble lignin Measured using UV-vis spectrophotometer Calculated from absorption at 205 nm 8
Lignin content and composition Klason lignin Miscanthus: 25 % Loblolly pine: 29 % Sweetgum: 26 % Aid Acid soluble lbl lignini Miscanthus: 1.1 % Loblolly pine: 0.5 % Sweetgum: 26% 2.6 6 5 2 1 2 3 O 4 3 3 O 2 2 1 1 6 2 6 2 5 3 5 3 4 O 3 4 Guaiacyl Syringyl p-coumaryl SW x x HW x x x Grass x x x 9
Carbohydrate analysis 40 mesh extractive free wood Hydrolyzed y with 72 % H 2 SO 4 Diluted to 3% H 2 SO 4 and autoclaved at 121 C for 1 hour Sugars measured using HPLC with pulsed amperometric detector 10
Carbohydrate profile 60.0 55.0 50.0 HO O tarting mat terial % dry weight of s 45.0 40.0 35.0 30.0 25.0 20.00 15.0 10.00 HO O HO 2 O O Miscanthus Sweetgum L.Pine 2 O 11 5.0 0.0 Arabinose Galactose Glucose Xylose Mannose
Solid-state 13 C NMR of miscanthus Lignin C=O Lignin Phenolic Cellulose Lignin -O 3 Hemicellulose R-CO 3 12
Cellulose extraction Holocellulose = Cellulose + Hemicellulose Obtained by treating extractive free wood repeatedly with acetic acid and sodium chlorite Yield: 74% (by dry wt. of miscanthus) Cellulose Boil holocellulose with 2.5 M HCl at 100 CC for 4 hours Yield: 55% (by dry wt. of holocellulose) 13
Cellulose structure and crystallinity y Solid-state 13 C CP/MAS NMR of cellulose Cellulose structure and crystallinity O 4 6 2 3 O 2 1 O 2 O 1 C2,3,5 C1 C4 C6 14
Cellulose structure and crystallinity y Degree of crystallinity : 48.9 % Loblolly pine:63 %; Sweetgum: 53.3% 3% Crystalline + para crystalline Amorphous 15
Milled wood lignin Purest form of lignin that can be isolated Wood extracted with ethanol and ethanol/benzene Milled for 130 hours Extracted with 96% Dioxane for 48 hours Dioxane collected, dried and lignin purified 16
Milled wood lignin 13 C NMR 5 6 2 1 2 6 2 2 1 1 2 6 3 5 3 5 O 4 3 3 O 4 O 3 4 Guaiacyl (g) Syringyl (s) p-coumaryl (h) 2 3 -O 3 h-4 s and g 4-O-5 α-co/ β-o-4 β-5 COOR 17
Lignin molecular weight Lignin acetylated and Mn Mw D dissolved in THF Molecular weight distribution measured using gel permeation chromatography h Miscanthus 8.33e 3 1.38e 4 1.65 Sweetgum 9.41e 3 1.6e 4 1.70 L.Pine 7.58e 3 1.34e 4 1.77 18
Thank You! 19