title: Using sulfite chemistry for robust bioconversion of Douglas-fir forest residue to bioethanol at high titer and lignosulfonate: a pilot-scale evaluation.
abstract: This study demonstrated at the pilot-scale (50 kg) use of Douglas-fir forest harvest residue, an underutilized forest biomass, for the production of high titer and high yield bioethanol using sulfite chemistry without solid-liquor separation and detoxification. Sulfite Pretreatment to Overcome the Recalcitrance of Lignocelluloses (SPORL) was directly applied to the ground forest harvest residue with no further mechanical size reduction, at a low temperature of 145°C and calcium bisulfite or total SO2 loadings of only 6.5 or 6.6 wt% on oven dry forest residue, respectively. The low temperature pretreatment facilitated high solids fermentation of the un-detoxified pretreated whole slurry. An ethanol yield of 282 L/tonne, equivalent to 70% theoretical, with a titer of 42 g/L was achieved. SPORL solubilized approximately 45% of the wood lignin as directly marketable lignosulfonate with properties equivalent to or better than a commercial lignosulfonate, important to improve the economics of biofuel production.
authors.affiliation: USDA Forest Service, Forest Products Lab, Madison, WI, USA. Electronic address: jzhu@fs.fed.us.
authors.forename: J Y
authors.initials: JY
authors.lastname: Zhu
authors.affiliation: USDA Forest Service, Forest Products Lab, Madison, WI, USA; Dept. of Microbiology, Yogi Vemana University, Kadapa, India.
authors.forename: M Subhosh
authors.initials: MS
authors.lastname: Chandra
authors.affiliation: Jiangsu Provincial Key and Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing, China; USDA Forest Service, Forest Products Lab, Madison, WI, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Gu
authors.affiliation: USDA Forest Service, Forest Products Lab, Madison, WI, USA.
authors.forename: Roland
authors.initials: R
authors.lastname: Gleisner
authors.affiliation: USDA Forest Service, Forest Products Lab, Madison, WI, USA.
authors.forename: Rick
authors.initials: R
authors.lastname: Reiner
authors.affiliation: College of Forestry, Oregon State University, Corvallis, OR, USA.
authors.forename: John
authors.initials: J
authors.lastname: Sessions
authors.affiliation: Weyerhaeuser Company, Federal Way, WA, USA.
authors.forename: Gevan
authors.initials: G
authors.lastname: Marrs
authors.affiliation: Weyerhaeuser Company, Federal Way, WA, USA.
authors.forename: Johnway
authors.initials: J
authors.lastname: Gao
authors.affiliation: Weyerhaeuser Company, Federal Way, WA, USA.
authors.forename: Dwight
authors.initials: D
authors.lastname: Anderson
mesh_terms: D056804:Biofuels; D001709:Biotechnology / Q000379:methods*; D050260:Carbohydrate Metabolism; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D065928:Forests; D006863:Hydrogen-Ion Concentration; D008031:Lignin / Q000031:analogs & derivatives* / Q000378:metabolism; D008970:Molecular Weight; D010865:Pilot Projects; D028224:Pseudotsuga / Q000737:chemistry*; D013379:Substrate Specificity; D013447:Sulfites / Q000737:chemistry*; D013455:Sulfur / Q000032:analysis; D013696:Temperature; D013997:Time Factors; D014934:Wood / Q000737:chemistry
chemical_list: D056804:Biofuels; D013447:Sulfites; C036909:lignocellulose; D000431:Ethanol; D013455:Sulfur; C001545:lignosulfuric acid; D008031:Lignin
keywords: Forest residues; High titer biofuel; Lignosulfonate; Pretreatment; Sulfite pulping