Xylose transport studies with xylose-utilizing Saccharomyces cerevisiae strains expressing heterologous and homologous permeases

Anu Saloheimo, Jenita Rauta, Oleh V. Stasyk, Andrei A. Sibirny, Merja Penttilä, Laura Ruohonen (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

135 Citations (Scopus)

Abstract

In the present study, we modified xylose uptake properties of a recombinant xylose-utilizing yeast Saccharomyces cerevisiae by expression of heterologous and homologous permease-encoding genes. In a mutant yeast strain with the main seven hexose transporter genes deleted, and engineered for xylose utilization, we screened an expression cDNA library of the filamentous fungus Trichoderma reesei (Hypocrea jecorina) for enhanced growth on xylose plates. One cDNA clone with significant homology to fungal sugar transporters was obtained, but when the clone was retransformed into the host, it did not support significant growth on xylose. However, during a long liquid culture of the strain carrying the cDNA clone, adaptive mutations apparently occurred in the host, which led to growth on xylose but not on glucose. The new transporter homologue, Trxlt1 thus appears to code for a protein specific for xylose uptake. In addition, xylose-transporting properties of some homologous hexose transporters were studied. All of them, i.e., Hxt1, Hxt2, Hxt4, and Hxt7 were capable of xylose uptake. Their affinities for xylose varied, Km values between 130 and 900 mM were observed. The single-Hxt strains showed a biphasic growth mode on xylose, alike the Trxlt1 harboring strain. The initial, slow growth was followed by a long lag and finally by exponential growth.

Original languageEnglish
Pages (from-to)1041-1052
JournalApplied Microbiology and Biotechnology
Volume74
Issue number5
DOIs
Publication statusPublished - 1 Apr 2007
MoE publication typeA1 Journal article-refereed

Keywords

  • Adaptive mutation(s)
  • Hexose transporters
  • Saccharomyces cerevisiae
  • Trichoderma reesei transporter
  • Xylose uptake

Fingerprint Dive into the research topics of 'Xylose transport studies with xylose-utilizing Saccharomyces cerevisiae strains expressing heterologous and homologous permeases'. Together they form a unique fingerprint.

Cite this