title: High titer ethanol production from simultaneous enzymatic saccharification and fermentation of aspen at high solids: a comparison between SPORL and dilute acid pretreatments.
abstract: Native aspen (Populus tremuloides) was pretreated using sulfuric acid and sodium bisulfite (SPORL) and dilute sulfuric acid alone (DA). Simultaneous enzymatic saccharification and fermentation (SSF) was conducted at 18% solids using commercial enzymes with cellulase loadings ranging from 6 to 15 FPU/g glucan and Saccharomyces cerevisiae Y5. Compared with DA pretreatment, the SPORL pretreatment reduced the energy required for wood chip size-reduction, and reduced mixing energy of the resultant substrate for solid liquefaction. Approximately 60% more ethanol was produced from the solid SPORL substrate (211 L/ton wood at 59 g/L with SSF efficiency of 76%) than from the solid DA substrate (133 L/ton wood at 35 g/L with SSF efficiency 47%) at a cellulase loading of 10 FPU/g glucan after 120 h. When the cellulase loading was increased to 15 FPU/g glucan on the DA substrate, the ethanol yield still remained lower than the SPORL substrate at 10 FPU/g glucan.
authors.affiliation: USDA Forest Service, Forest Products Laboratory, Madison, WI, USA. jzhu@fs.fed.us
authors.forename: J Y
authors.initials: JY
authors.lastname: Zhu
authors.forename: R
authors.initials: R
authors.lastname: Gleisner
authors.forename: C T
authors.initials: CT
authors.lastname: Scott
authors.forename: X L
authors.initials: XL
authors.lastname: Luo
authors.forename: S
authors.initials: S
authors.lastname: Tian
mesh_terms: D056804:Biofuels; D002480:Cellulase / Q000378:metabolism*; D002849:Chromatography, Gas; D002852:Chromatography, Ion Exchange; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D032107:Populus / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013447:Sulfites; D013464:Sulfuric Acids
chemical_list: D056804:Biofuels; D013447:Sulfites; D013464:Sulfuric Acids; D000431:Ethanol; D002480:Cellulase; C033158:sulfuric acid; C009279:sodium bisulfite