title: The effect of bark on sulfur dioxide-ethanol-water fractionation and enzymatic hydrolysis of forest biomass.
abstract: The focus of this study was to find out the effect of bark on SO2-ethanol-water (SEW) fractionation and enzymatic hydrolysis of forest biomass. Softwood bark was found to be more harmful than hardwood bark in both processes. For softwood, the amount of undigested wood in SEW fractionation increased with the increasing bark content, whereas the hardwood bark did not impair the fractionation of wood. The higher the softwood bark content was the lower were the yields in enzymatic hydrolysis likely due to the unproductive binding of enzymes on lignin and other compounds. Addition of surfactant Tween 20 (2% w/w on substrate) prior to enzyme more than doubled the sugar yield of bark-rich softwood pulp. Hardwood bark impaired enzymatic hydrolysis when its share was over 28%. According to a preliminary study, lignosulfonates from the carry-over liquor seem to improve the sugar yield in the enzymatic hydrolysis by acting as a surfactant.
authors.affiliation: Department of Forest Products Technology, Aalto University, FI- 00076 Aalto, Finland. Electronic address: minna.yamamoto@aalto.fi.
authors.forename: Minna
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Forest Products Technology, Aalto University, FI- 00076 Aalto, Finland; Department of Biotechnology and Chemical Technology, Aalto University, FI- 00076 Aalto, Finland.
authors.forename: Tuomas
authors.initials: T
authors.lastname: Niskanen
authors.affiliation: Department of Forest Products Technology, Aalto University, FI- 00076 Aalto, Finland.
authors.forename: Mikhail
authors.initials: M
authors.lastname: Iakovlev
authors.affiliation: Department of Biotechnology and Chemical Technology, Aalto University, FI- 00076 Aalto, Finland.
authors.forename: Heikki
authors.initials: H
authors.lastname: Ojamo
authors.affiliation: Department of Forest Products Technology, Aalto University, FI- 00076 Aalto, Finland; Department of Chemical and Biological Engineering, University of Maine, 5737 Jenness Hall, Orono, ME 04469-5737, USA. Electronic address: AvanHeiningen@umche.maine.edu.
authors.forename: Adriaan
authors.initials: A
authors.lastname: van Heiningen
mesh_terms: D018533:Biomass; D002480:Cellulase / Q000378:metabolism*; D005591:Chemical Fractionation; D000431:Ethanol / Q000737:chemistry*; D065928:Forests; D006868:Hydrolysis / Q000187:drug effects; D024301:Plant Bark / Q000737:chemistry* / Q000187:drug effects; D011136:Polysorbates / Q000494:pharmacology; D013458:Sulfur Dioxide / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014934:Wood / Q000737:chemistry / Q000187:drug effects
chemical_list: D011136:Polysorbates; D014867:Water; D013458:Sulfur Dioxide; D000431:Ethanol; D002480:Cellulase
keywords: Bark; Biomass; Enzymatic hydrolysis; SO(2)–ethanol–water fractionation; Surfactant