title: Enhancement of xylitol production by attenuation of intracellular xylitol dehydrogenase activity in Candida tropicalis.
abstract: To construct Candida tropicalis strains that produce a high yield of xylitol with no requirement for co-substrates, we engineered the yeast with an attenuated xylitol dehydrogenase (XDH) and then assessed the efficiency of xylitol production The mutants, strains XDH-5 (with only one copy of the XDH gene), and ARSdR-16 (with a mutated XDH gene) showed 70 and 40% of wild type (WT) XDH activity, respectively. Conversions of xylose to xylitol by WT, XDH-5, and ARSdR-16 were 62, 64, and 75%, respectively, with productivities of 0.52, 0.54, and 0.62 g l(-1) h(-1), respectively. The ARSdR-16 mutant strain produced xylitol with high yield and high productivity in a simple process that required no co-substrates, such as glycerol. This strain represents a promising alternative for efficient and cost-effective xylitol production.
authors.affiliation: Higher Education Center for Bioregulator Research, Chonnam National University, Gwangju, 500-757, Korea.
authors.forename: Byoung Sam
authors.initials: BS
authors.lastname: Ko
authors.forename: Dong-Min
authors.initials: DM
authors.lastname: Kim
authors.forename: Byoung Hoon
authors.initials: BH
authors.lastname: Yoon
authors.forename: Suk
authors.initials: S
authors.lastname: Bai
authors.forename: Hyeon Yong
authors.initials: HY
authors.lastname: Lee
authors.forename: Jung Hoe
authors.initials: JH
authors.lastname: Kim
authors.forename: Il-Chul
authors.initials: IC
authors.lastname: Kim
mesh_terms: D001483:Base Sequence; D001709:Biotechnology; D041022:Candida tropicalis / Q000235:genetics* / Q000378:metabolism*; D050542:D-Xylulose Reductase / Q000235:genetics* / Q000378:metabolism*; D004271:DNA, Fungal / Q000235:genetics; D005285:Fermentation; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005800:Genes, Fungal; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D015202:Protein Engineering; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014993:Xylitol / Q000096:biosynthesis*; D014994:Xylose / Q000378:metabolism
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D050505:Mutant Proteins; D011994:Recombinant Proteins; D014994:Xylose; D050542:D-Xylulose Reductase; D014993:Xylitol