Production of Xylitol from D-Xylose by Overexpression of Xylose Reductase in Osmotolerant Yeast Candida glycerinogenes WL2002-5

Appl Biochem Biotechnol. 2015 Jul;176(5):1511-27. doi: 10.1007/s12010-015-1661-8. Epub 2015 May 28.

Abstract

Efficient bioconversion of D-xylose into various biochemicals is critical for the developing lignocelluloses application. In this study, we compared D-xylose utilization in Candida glycerinogenes WL2002-5 transformants expressing xylose reductase (XYL1) in D-xylose metabolism. C. glycerinogenes WL2002-5 expressing XYL1 from Schefferomyces stipitis can produce xylitol. Xylitol production by the recombinant strains was evaluated using a xylitol fermentation medium with glucose as a co-substrate. As glucose was found to be an insufficient co-substrate, various carbon sources were screened for efficient cofactor regeneration, and glycerol was found to be the best co-substrate. The effects of glycerol on the xylitol production rate by a xylose reductase gene (XYL1)-overexpressed mutant of C. glycerinogenes WL2002-5 were investigated. The XYL1-overexpressed mutant produced xylitol from D-xylose using glycerol as a co-substrate for cell growth and NAD (P) H regeneration: 100 g/L D-xylose was completely converted into xylitol when at least 20 g/L glycerol was used as a co-substrate. XYL1 overexpressed mutant grown on glycerol as co-substrate accumulated 2.1-fold increased xylitol concentration over those cells grown on glucose as co-substrate. XYL1 overexpressed mutant produced xylitol with a volumetric productivity of 0.83 g/L/h, and a xylitol yield of 98 % xylose. Recombinant yeast strains obtained in this study are promising candidates for xylitol production. This is the first report of XYL1 gene overexpression of C. glycerinogenes WL2002-5 for enhancing the efficiency of xylitol production.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological* / drug effects
  • Aldehyde Reductase / metabolism*
  • Candida / drug effects
  • Candida / enzymology*
  • Candida / genetics
  • Electrophoresis, Polyacrylamide Gel
  • Fermentation / drug effects
  • Fluorescence
  • Gene Dosage
  • Genes, Fungal
  • Glucose / metabolism
  • Glycerol / pharmacology
  • Kinetics
  • Osmosis* / drug effects
  • Real-Time Polymerase Chain Reaction
  • Recombination, Genetic / genetics
  • Reference Standards
  • Substrate Specificity / drug effects
  • Time Factors
  • Xylitol / biosynthesis*
  • Xylose / biosynthesis*

Substances

  • Xylose
  • Aldehyde Reductase
  • Glucose
  • Glycerol
  • Xylitol