References
Lee J. 1997. Biological conversion of lignocellulosic biomass to ethanol.
J Biotechnol 56:1–24.
Chakar FS, Ragauska AJ. 2004. Review of current and future softwood kraft
lignin process chemistry. Ind Crop Prod 20:131–141.
Lee SH, Lee SB. 2005. The Hildebrand solubility parameters, cohesive
energy densities and internal energies of 1-alkyl-3-methylimidazo-
lium-based room temperature ionic liquids. Chem Commun
27:3469–3471.
Chandra RP, Bura R, Mabee WE, Berlin A, Pan B, Saddler JN. 2007.
Substrate pretreatment: The key to effective enzymatic hydrolysis of
lignocellulosics? Adv Biochem Eng Biotechnol 108:67–93.
Chang VS, Holtzapple M. 2000. Fundamental factors affecting biomass
enzymatic reactivity. Appl Biochem Biotechnol 84–86:5–37.
Chum HL, Johnson DK, Black S. 1988. Organosolv pretreatment for
enzymatic hydrolysis of poplars: 1. Enzymatic hydrolysis of cellulosic
residues. Biotechnol Bioeng 31:643–649.
Li C, Wang Q, Zhao ZK. 2008. Acid in ionic liquid: An efficient system for
hydrolysis of lignocellulose. Green Chem 10:177–182.
Liu LY, Chen HZ. 2006. Enzymatic hydrolysis of cellulose materials treated
with ionic liquid [Bmim]Cl. Chin Sci Bull 51:2432–2436.
Mes-Hartree M, Dale BE, Craig WK. 1988. Comparison of steam and
ammonia pretreatment for enzymatic hydrolysis of cellulose. Appl
Microbiol Biotechnol 29:462–468.
Crowhurst L, Mawdsley PR, Perez-Arlandis JM, Salter PA, Welton T. 2003.
Solvent-solute interactions in ionic liquids. Phys Chem Chem Phys
5:2790–2794.
Miller GL. 1959. Use of dinitrosalicylic acid reagent for determination of
reducing sugar. Anal Chem 31:426–428.
Dadi AP, Varanasi S, Schall CA. 2006. Enhancement of cellulose sacchar-
ification kinetics using an ionic liquid pretreatment step. Biotechnol
Bioeng 95:904–910.
Mosier N, Wyman C, Dale B, Elander R, Lee YY, Holtzapple M, Ladisch M.
2005. Features of promising technologies for pretreatment of ligno-
cellulosic biomass. Bioresour Technol 96:673–686.
Dadi AP, Schall CA, Varanasi S. 2007. Mitigation of cellulose recalcitrance
to enzymatic hydrolysis by ionic liquid pretreatment. Appl Biochem
Biotechnol 136-140:407–421.
Moulthrop JS, Swatloski RP, Moyna G, Rogers RD. 2005. High-resolution
13C NMR studies of cellulose and cellulose oligomers in ionic liquid
solutions. Chem Commun 12:1557–1559.
Estager J, Leveque JM, Cravotto G, Boffa L, Bonrath W, Draye M. 2007.
One-pot and solventless synthesis of ionic liquids under ultrasonic
irradiation. Synlett 13:2065–2068.
NREL. 1996. Technical report. Biomass analysis technology team laboratory
analytical procedure. Golden, CO: National Renewable Energy Labora-
tory.
Fort DA, Remsing RC, Swatloski RP, Moyna P, Moyna G, Rogers RD. 2007.
Can ionic liquids dissolve wood? Processing and analysis of lignocel-
lulosic materials with 1-n-butyl-3-methylimidazolium chloride. Green
Chem 9:63–69.
Ooshima H, Sakata M, Harano Y. 1986. Enhancement of enzymatic
hydrolysis of cellulose by surfactant. Biotechnol Bioeng 28:1727–
1734.
Pu Y, Jiang N, Ragauskas AJ. 2007. Ionic liquid as a green solvent for lignin.
J Wood Chem Technol 27:23–33.
Freemantle M. 1998. Designer solvents—Ionic liquids may boost clean
technology. Chem Eng News 76:32–37.
Sheldon RA, Lau RM, Sorgedrager MJ, van Rantwijk F. 2002. Biocatalysis in
ionic liquids. Green Chem 4:147–151.
Fukaya Y, Sugimoto A, Ohno H. 2006. Superior solubility of polysacchar-
ides in low viscosity, polar, and halogen-free 1,3-dialkylimidazolium
formates. Biomacromolecules 7:3295–3297.
Sun Y, Cheng J. 2002. Hydrolysis of lignocellulosic materials for ethanol
production: A review. Bioresour Technol 83:1–11.
Fukaya Y, Hayashi K, Wada M, Ohno H. 2008. Cellulose dissolution with
polar ionic liquids under mild conditions: Required factors for anions.
Green Chem 10:44–46.
Swiderski K, McLean A, Gordon CM, Vaughan DH. 2004. Estimates of
internal energies of vaporisation of some room temperature ionic
liquids. Chem Commun 19:2178–2179.
Galbe M, Zacchi G. 2007. Pretreatment of lignocellulosic materials for efficient
bioethanol production. Adv Biochem Eng Biotechnol 108:41–65.
Gierer J, Noren I. 1982. Oxidative pretreatment of pine wood to facilitate
delignification during kraft pulping. Holzforschung 36:123–130.
Grous WR, Converse AO, Grethlein HE. 1986. Effect of steam explosion
pretreatment on pore size and enzymatic hydrolysis of poplar. Enzyme
Microb Technol 8:274–280.
Thielemans W, Wool RP. 2005. Lignin esters for use in unsaturated
thermosets: Lignin modification and solubility modeling. Biomacro-
molecules 6:1895–1905.
Thygesen A, Oddershede J, Lilholt H, Thomsen AB, Stahl K. 2005. On the
determination of crystallinity and cellulose content in plant fibres.
Cellulose 12:563–576.
Waterkamp DA, Heiland M, Schluter M, Sauvageau JC, Beyersdorff T,
Thoming J. 2007. Synthesis of ionic liquids in micro-reactors—A
process intensification study. Green Chem 9:1084–1090.
Zhang Y-HP, Ding S-Y, Mielenz JR, Cui J-B, Elander RT, Laser M, Himmel
ME, McMillan JR, Lynd LR. 2007. Fractionating recalcitrant lignocel-
lulose at modest reaction conditions. Biotechnol Bioeng 97:214–
223.
Hatakka AI. 1983. Pretreatment of wheat straw by white-rot fungi for
enzymatic saccharification of cellulose. Eur J Appl Microbiol Biotech-
nol 18:350–357.
Himmel ME, Ding S-Y, Johnson DK, Andey WS, Nimlos MR, Brady JW,
Foust TD. 2007. Biomass recalcitrance: Engineering plants and enzymes
for biofuels production. Science 315:804–807.
Kadla JF, Kubo S, Venditti RA, Gilbert RD, Compere AL, Griffith W. 2002.
Lignin-based carbon fibers for composite fiber applications. Carbon
40:2913–2920.
Zhao H, Baker GA, Song Z, Olubajo O, Crittle T, Peters D. 2008. Designing
enzyme-compatible ionic liquids that can dissolve carbohydrates.
Green Chem 10:696–705.
Kamiya N, Matsushita Y, Hanaki M, Nakashima K, Narita M, Goto M,
Takahashi H. 2008. Enzymatic in situ saccharification of cellulose in
aqueous-ionic liquid media. Biotechnol Lett 30:1037–1040.
Zhu SD, Wu YX, Chen QM, Yu ZN, Wang CW, Jin SW, Ding YG, Wu G.
2006. Dissolution of cellulose with ionic liquids and its application: A
mini-review. Green Chem 8:325–327.
¨
Kilpelainen I, Xie H, King A, Granstrom M, Heikkinen S, Agrgyropoulos
Zhu L, O’Dwyer JP, Chang VS, Granda CB, Holtzapple MT. 2008. Structural
features affecting biomass enzymatic digestibility. Bioresour Technol
99:3817–3828.
DS. 2007. Dissolution of wood in ionic liquids. J Agric Food Chem
55:9142–9148.
1376
Biotechnology and Bioengineering, Vol. 102, No. 5, April 1, 2009