title: Bioconversion of Birch Wood Hemicellulose Hydrolyzate to Xylitol.
abstract: A sugar solution containing 42.9 g l(-1) of xylose was prepared from the wood of Japanese white birch (Betula platyphylla var. japonica) by hydrolysis with 3 % sulfuric acid with a liquor-to-solid ratio of 4 (g g(-1)) at 120 °C for 1 h. During the acid hydrolysis, undesirable by-products were generated, such as acetic acid, furfural, and low-molecular-weight phenols, which inhibit bioconversion of xylose to xylitol. These inhibitors were successfully removed from the hydrolyzate by sorption onto a steam-activated charcoal followed by treatment with an anion exchange resin. Bioconversion of the detoxified hydrolyzate to xylitol by the yeast Candida magnoliae was investigated under the microaerobic conditions. The oxygen transfer rate (OTR) varied from 9.6 to 22.3 mmol O2 l(-1) h(-1). The best fermentative performance of C. magnoliae in the birch wood hydrolyzate (xylitol yield 0.74 g xylitol g xylose(-1); volumetric productivity 1.0 g l(-1) h(-1)) was obtained at the OTR of 12.6 mmol O2 l(-1) h(-1).
authors.affiliation: Department of Biotechnology and Environmental Chemistry, Kitami Institute of Technology, 165 Koen-cho, Kitami, 090-8507, Japan, miyabi.kou98@gmail.com.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Miura
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Shimotori
authors.forename: Hisayuki
authors.initials: H
authors.lastname: Nakatani
authors.forename: Akira
authors.initials: A
authors.lastname: Harada
authors.forename: Masakazu
authors.initials: M
authors.lastname: Aoyama
mesh_terms: D029662:Betula / Q000737:chemistry*; D001711:Biotransformation; D002175:Candida / Q000378:metabolism; D006868:Hydrolysis; D010100:Oxygen / Q000378:metabolism; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D014934:Wood / Q000737:chemistry*; D014993:Xylitol / Q000378:metabolism*
chemical_list: D011134:Polysaccharides; C007916:hemicellulose; D010100:Oxygen; D014993:Xylitol