Bioenergetic consequences of catabolic shifts by Lactobacillus plantarum in response to shifts in environmental oxygen and pH in chemostat cultures

Ching-Ping Tseng, J. L. Tsau, T. J. Montville*

*Corresponding author for this work

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

Proton motive force (PMF), intracellular end product concentrations, and ATP levels were determined when a steady-state Lactobacillus plantarum 8014 anaerobic chemostat culture was shifted to an aerobic condition or was shifted from pH 5.5 to 7.5. The PMF and intracellular ATP levels increased immediately after the culture was shifted from anaerobic to aerobic conditions. The concentrations of intracellular lactate and acetate, which exported protons that contributed to the proton gradient, changed in the same fashion. The H+/lactate stoichiometry, n, varied from 0.8 to 1.2, and the H+/acetate n value changed from 0.8 to 1.6 at 2 h after the shift to aerobic conditions. The n value for acetate excretion remained elevated at aerobic steady state. When the anaerobic culture was shifted from pH 5.5 to 7.5, intracellular ATP increased 20% immediately even though the PMF decreased 50% as a result of the depletion of the transmembrane proton gradient. The H+/lactate n value changed from 0.7 to 1.8, and n for H+/acetate increased from 0.9 to 1.9 at pH 7.5 steady state. In addition, the H+/acetate stoichiometry was always higher than the n value for H+/lactate; both were higher in alkaline than aerobic conditions, demonstrating that L. plantarum 8014 coexcreted more protons with end products to maintain intracellular pH homeostasis and generate proton gradients under aerobic and alkaline conditions. During the transient to pH 7.5, the n value for H+/acetate approached 3, which would spare one ATP.

Original languageEnglish
Pages (from-to)4411-4416
Number of pages6
JournalJournal of Bacteriology
Volume173
Issue number14
DOIs
StatePublished - 1 Jan 1991

Fingerprint Dive into the research topics of 'Bioenergetic consequences of catabolic shifts by Lactobacillus plantarum in response to shifts in environmental oxygen and pH in chemostat cultures'. Together they form a unique fingerprint.

  • Cite this