Phosphoketolase pathway for Xylose Catabolism in Clostridium acetobutylicum revealed by 13C metabolic flux analysis

Lixia Liu, Lei Zhang, Wei Tang, Yang Gu, Qiang Hua, Sheng Yang, Weihong Jiang, Chen Yang

Research output: Contribution to journalArticlepeer-review

48 Scopus citations

Abstract

Solvent-producing clostridia are capable of utilizing pentose sugars, including xylose and arabinose; however, little is known about how pentose sugars are catabolized through the metabolic pathways in clostridia. In this study, we identified the xylose catabolic pathways and quantified their fluxes in Clostridium acetobutylicum based on [1-13C]xylose labeling experiments. The phosphoketolase pathway was found to be active, which contributed up to 40% of the xylose catabolic flux in C. acetobutylicum. The split ratio of the phosphoketolase pathway to the pentose phosphate pathway was markedly increased when the xylose concentration in the culture medium was increased from 10 to 20 g liter-1. To our knowledge, this is the first time that the in vivo activity of the phosphoketolase pathway in clostridia has been revealed. A phosphoketolase from C. acetobutylicum was purified and characterized, and its activity with xylulose-5-P was verified. The phosphoketolase was overexpressed in C. acetobutylicum, which resulted in slightly increased xylose consumption rates during the exponential growth phase and a high level of acetate accumulation.

Original languageEnglish (US)
Pages (from-to)5413-5422
Number of pages10
JournalJournal of Bacteriology
Volume194
Issue number19
DOIs
StatePublished - Oct 2012

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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