What question did this study set out to answer?

Determine whether acetic acid accumulation halts Clostridium thermoaceticum growth by acting as a membrane uncoupler that acidifies the cytoplasm.

December 1, 1984Applied and Environmental MicrobiologyOpen Access

Uncoupling by Acetic Acid Limits Growth of and Acetogenesis by Clostridium thermoaceticum

View Full Paper

Ask AI

Bookmark

Authors

JBJerald J. BaronofskyBoston University WSW J SchreursColorado State University EKEva R. KashketBoston University

Discussion

Member takes

Implication

Laboratory study demonstrates that acetic acid dissipates proton motive force in Clostridium thermoaceticum, suggesting single mutations cannot easily confer acid tolerance.

Key Points

Determine whether acetic acid accumulation halts Clostridium thermoaceticum growth by acting as a membrane uncoupler that acidifies the cytoplasm.
Monitored batch cultures homofermenting glucose to acetic acid to evaluate internal pH and transmembrane electrical potential across extracellular pH changes from 7 to 5.
Measured transmembrane electrical potential and internal pH dissipation in nongrowing stationary-phase cells suspended in citrate-phosphate buffer exposed to organic acids, ionophores, and metabolic inhibitors.
Growing cells maintained an internal pH 0.6 units above the medium, while transmembrane potential fell from 140 mV at pH 7 to 80 mV at pH 5, reducing total proton motive force from 155 mV to 120 mV.
Acidification below pH 5 caused complete collapse of both the transmembrane electrical potential and the pH gradient, indicating viable cells require an internal pH of at least 5.5 to 5.7.
In nongrowing cells at external pH 5.0, un-ionized acetic acid freely traversed the cytoplasmic membrane and eliminated the 1.5-unit pH gradient, mimicking classical proton ionophores.

Cite This Study

Baronofsky et al. (1984) studied this question.

synapsesocial.com/papers/6a776ae2576efb0ddaf7537b https://doi.org/10.1128/aem.48.6.1134-1139.1984

View Full Paper

Ask AI

Bookmark

Implication

Laboratory study demonstrates that acetic acid dissipates proton motive force in Clostridium thermoaceticum, suggesting single mutations cannot easily confer acid tolerance.

Uncoupling by Acetic Acid Limits Growth of and Acetogenesis by Clostridium thermoaceticum

Discussion

Member takes

Implication

Key Points

Cite This Study

Uncoupling by Acetic Acid Limits Growth of and Acetogenesis by Clostridium thermoaceticum

Discussion

Member takes

Implication

Key Points

Cite This Study

Also Consider

Also Consider