Cellobiose uptake and metabolism by Ruminococcus flavefaciens

C. T. Helaszek, B. A. White

Research output: Contribution to journalArticlepeer-review

Abstract

The cellulolytic ruminal bacterium Ruminococcus flavefaciens FD-1 utilizes cellobiose but not glucose as a substrate for growth. Cellobiose uptake by R. flavefaciens FD-1 was measured under anaerobic conditions (N2), using [G-3H]cellobiose. The rate of cellobiose uptake for early- or late-log-phase cellobiose-grown cells was 9 nmol/min per mg of whole-cell protein. Cellobiose uptake was inhibited by electron transport inhibitors, iron-reactive compounds, proton ionophores, sulfhydryl inhibitors, N,N-dicyclohexylcarbodiimide, and NaF as well as lasalocid and monensin. The results support the existence of an active transport system for cellobiose. Transport of [U-14C]glucose was not detected with this system. Phosphorylation of cellobiose was not by a phosphoenolpyruvate-dependent system. Cellobiose phosphorylase activity was detected by both a coupled spectrophotometric assay and a discontinuous assay. The enzyme was produced constitutively in cellobiose-grown cells at a specific activity of 329 nmol/min per mg of cell-free extract protein.

Original languageEnglish (US)
Pages (from-to)64-68
Number of pages5
JournalApplied and environmental microbiology
Volume57
Issue number1
StatePublished - Jan 28 1991

ASJC Scopus subject areas

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

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