title: Structural features affecting the enzymatic digestibility of pine wood pretreated with ionic liquids.
abstract: Pretreating lignocellulosic biomass with certain ionic liquids results in structural and chemical changes that make the biomass more digestible by enzymes. In this study, pine wood was pretreated with 1-ethyl-3-methylimidazolium chloride/acetate ([C2 mim]Cl and [C2 mim][OAc]) at different temperatures to investigate the relative importance of substrate features, such as accessible surface area, cellulose crystallinity, and lignin content, on enzymatic digestibility. The ionic liquid pretreatments resulted in glucan conversions ranging from 23% to 84% on saccharification of the substrates, with [C2 mim][OAc] being more effective than [C2 mim]Cl. The pretreatments resulted in no delignification of the wood, some loss of cellulose crystallinity under certain conditions, and varying levels of increased surface area. Enzymatic digestibility closely correlated with accessible surface area and porosity measurements obtained using Simons' staining and thermoporosimetry techniques. Increased accessible surface area was identified as the principal structural feature responsible for the improved enzymatic digestibility.
authors.affiliation: Scion, Private Bag 3020, Rotorua, 3046, New Zealand. kirk.torr@scionresearch.com.
authors.forename: Kirk M
authors.initials: KM
authors.lastname: Torr
authors.affiliation: Scion, Private Bag 3020, Rotorua, 3046, New Zealand.
authors.forename: Karen T
authors.initials: KT
authors.lastname: Love
authors.affiliation: Joint BioEnergy Institute, Emeryville, California, 94608.|Sandia National Laboratories, Livermore, California, 94551.
authors.forename: Blake A
authors.initials: BA
authors.lastname: Simmons
authors.affiliation: Scion, Private Bag 3020, Rotorua, 3046, New Zealand.
authors.forename: Stefan J
authors.initials: SJ
authors.lastname: Hill
mesh_terms: D006867:Hydrolases / Q000378:metabolism*; D007093:Imidazoles / Q000378:metabolism*; D052578:Ionic Liquids / Q000378:metabolism*; D008031:Lignin / Q000378:metabolism*; D028223:Pinus; D013696:Temperature; D014934:Wood / Q000187:drug effects*
chemical_list: D007093:Imidazoles; D052578:Ionic Liquids; C036909:lignocellulose; D008031:Lignin; D006867:Hydrolases; C518739:1-ethyl-3-methylimidazolium
keywords: accessible surface area; enzyme digestibility; ionic liquids; lignocellulosic biomass; pretreatment