title: NAD⁺-dependent xylitol dehydrogenase (xdhA) and L-arabitol-4-dehydrogenase (ladA) deletion mutants of Aspergillus oryzae for improved xylitol production.
abstract: Xylitol dehydrogenase (XDHA) and L-arabitol dehydrogenase (LADA) are two key enzymes in xylan metabolism catalyzing the oxidation of xylitol to D-xylulose and arabitol to L-xylulose, respectively. In Aspergillus oryzae, XDHA and LADA are encoded by xdhA and ladA. We deleted xdhA and ladA and xdhA-ladA to generate mutants with decreased dehydrogenase activities and increased xylitol production. The mutants were constructed by homologous transformation into A. oryzae P4 (∆pyrG) using pyrG as a selectable marker. The xylitol productivity of the mutants was measured using D-xylose as the sole carbohydrate source. xdhA, ladA, and the double-deletion mutant produced, respectively, 12.4 g xylitol/l with a yield of 0.24 g/g D-xylose, 12.4 g/l with a yield of 0.33 g/g D-xylose, and 8.6 g/l at a yield of 0.26 g/g D-xylose.
authors: The United Graduate School of Agricultural Science, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan. tunisona@yahoo.com
authors: A
authors: A
authors: Mahmud
authors: K
authors: K
authors: Hattori
authors: C
authors: C
authors: Hongwen
authors: N
authors: N
authors: Kitamoto
authors: T
authors: T
authors: Suzuki
authors: K
authors: K
authors: Nakamura
authors: K
authors: K
authors: Takamizawa
mesh_terms: D001236:Aspergillus oryzae / Q000235:genetics* / Q000378:metabolism*; D050542:D-Xylulose Reductase / Q000235:genetics* / Q000378:metabolism; D009005:Monosaccharides / Q000378:metabolism; D017384:Sequence Deletion; D013401:Sugar Alcohol Dehydrogenases / Q000235:genetics* / Q000378:metabolism; D014993:Xylitol / Q000032:analysis / Q000096:biosynthesis* / Q000378:metabolism; D014994:Xylose / Q000032:analysis / Q000378:metabolism
chemical_list: D009005:Monosaccharides; D014994:Xylose; D013401:Sugar Alcohol Dehydrogenases; C022751:D-arabinitol dehydrogenase; D050542:D-Xylulose Reductase; D014993:Xylitol