Direct conversion of xylan to ethanol by recombinant Saccharomyces cerevisiae strains displaying an engineered minihemicellulosome

Jie Sun, Fei Wen, Tong Si, Jian He Xu, Huimin Zhao

Research output: Contribution to journalArticle

Abstract

Arabinoxylan is a heteropolymeric chain of a β-1,4-linked xylose backbone substituted with arabinose residues, representing a principal component of plant cell walls. Here we developed recombinant Saccharomyces cerevisiae strains as whole-cell biocatalysts capable of combining hemicellulase production, xylan hydrolysis, and hydrolysate fermentation into a single step. These strains displayed a series of uni-, bi-, and trifunctional minihemicellulosomes that consisted of a miniscaffoldin (CipA3/CipA1) and up to three chimeric enzymes. The miniscaffoldin derived from Clostridium thermocellum contained one or three cohesin modules and was tethered to the cell surface through the S. cerevisiae a-agglutinin adhesion receptor. Up to three types of hemicellulases, an endoxylanase (XynII), an arabinofuranosidase (AbfB), and a β-xylosidase (XlnD), each bearing a C-terminal dockerin, were assembled onto the miniscaffoldin by high-affinity cohesin-dockerin interactions. Compared to uni- and bifunctional minihemicellulosomes, the resulting quaternary trifunctional complexes exhibited an enhanced rate of hydrolysis of arabinoxylan. Furthermore, with an integrated D-xylose-utilizing pathway, the recombinant yeast displaying the bifunctional minihemicellulosome CipA3-XynII-XlnD could simultaneously hydrolyze and ferment birchwood xylan to ethanol with a yield of 0.31 g per g of sugar consumed.

Original languageEnglish (US)
Pages (from-to)3837-3845
Number of pages9
JournalApplied and environmental microbiology
Volume78
Issue number11
DOIs
StatePublished - Jun 1 2012

ASJC Scopus subject areas

  • Biotechnology
  • Food Science
  • Applied Microbiology and Biotechnology
  • Ecology

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