A Kluyveromyces marxianus 2-deoxyglucose-resistant mutant with enhanced activity of xylose utilization

Authors

  • Suprayogi . 1Applied Molecular Bioscience, Graduate School of Medicine, Yamaguchi Univ., Ube, Japan. 2Dept. of Agroindustrial Technology, Fac. of Agriculture Technology, Brawijaya Univ., Malang, Indonesia.
  • Minh T. Nguyen 1Applied Molecular Bioscience, Graduate School of Medicine, Yamaguchi Univ., Ube, Japan. 2Dept. of Microbiology, Fac. of Environment, Vietnam National Univ. of Agriculture, Hanoi, Vietnam.
  • Noppon Lertwattanasakul Dept. of Microbiology, Fac. of Science, Kasetsart Univ., Bangkok, Thailand.
  • Nadchanok Rodrussamee Dept. of Biology, Fac. of Science, Chiang Mai Univ., Chiang Mai, Thailand.
  • Savitree Limtong Dept. of Microbiology, Fac. of Science, Kasetsart Univ., Bangkok, Thailand
  • Tomoyuki Kosaka Dept. of Biological Chemistry, Fac. of Agriculture, Yamaguchi Univ., Yamaguchi, Japan
  • Mamoru Yamada Applied Molecular Bioscience Graduate School of Medicine Yamaguchi University, Japan

Keywords:

Kluyveromyces marxianus, glucose repression, 2-deoxyglucose-resistant mutants, ethanol fermentation on xylose, thermotolerant yeast

Abstract

Thermotolerant ethanologenic yeast Kluyveromyces marxianus is capable of fermenting various sugars including xylose but glucose represses to hamper the utilization of other sugars. To acquire glucose repression-defective strains, 33 isolates as 2-deoxyglucose (2-DOG)-resistant mutants were acquired from about 100 colonies grown on plates containing 2-DOG, which were derived from an efficient strain DMKU 3-1042. According to the characteristics of sugar consumption abilities and cell growth and ethanol accumulation along with cultivation time, they were classified into three groups. The first group (3 isolates) utilized glucose and xylose in similar patterns along with cultivation to those of the parental strain, presumably due to reduction of the uptake of 2-DOG or enhancement of its export. The second group (29 isolates) showed greatly delayed utilization of glucose, presumably by reduction of the uptake or initial catabolism of glucose. The last group, only one isolate, showed enhanced utilization ability of xylose in the presence of glucose. Further analysis revealed that the isolate had a single nucleotide mutation to cause amino acid substitution (G270S) in RAG5 encoding hexokinase and exhibited very low activity of the enzyme. The possible mechanism of defectiveness of glucose repression in the mutant is discussed in this paper. [Int Microbiol 18(4):235-244 (2015)]

Keywords: Kluyveromyces marxianus · glucose repression · 2-deoxyglucose-resistant mutants · ethanol fermentation on xylose · thermotolerant yeast

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Issue

Vol. 18 No. 4 (2015)

Section

Research Articles

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