Authors: Oh Cheol Kim Surisa Suwannarangsee DooByoung Oh Seonghun Kim JeongWoo Seo Chul Ho Kim Hyun Ah Kang JeongYoon Kim Ohsuk Kwon
Publish Date: 2013/02/05
Volume: 36, Issue: 10, Pages: 1509-1518
Abstract
The thermotolerant methylotrophic yeast Hansenula polymorpha is able to grow at elevated temperature up to 48 °C as one of a few yeast strains which are naturally capable of alcoholic fermentation of xylose a pentose sugar abundant in lignocellulosic biomass However the current level of ethanol production from xylose by H polymorpha is still very low compared to those of other xylosefermenting strains Therefore it is necessary to analyze and remodel the xylose metabolism in H polymorpha at the whole genome level to identify and overcome these limits In the present study the transcriptomes of H polymorpha grown on xylose were compared with those of glucosegrown cells under both aerobic and microaerobic conditions Approximately two percent of H polymorpha genes were either up or downregulated by more than twofold during the growth on xylose The majority of the upregulated genes were involved in metabolism Some genes involved in xylose metabolism such as XYL1 XYL2 and TAL1 were also upregulated despite the fact that the differences in their induction level were only about threefold On the other hand the majority of the downregulated genes were involved in metabolism and cellular transport Interestingly some genes involved in glycolysis and ethanol fermentation were also repressed during growth on xylose suggesting that these genes are good targets for engineering H polymorpha to improve xylose fermentation
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