Transcriptomic analysis of carboxylic acid challenge in Escherichia coli: beyond membrane damage

Carboxylic acids are an attractive biorenewable chemical. Enormous progress has been made in engineering microbes for production of these compounds though titers remain lower than desired. Here we used transcriptome analysis of Escherichia coli during exogenous challenge with octanoic acid (C8) at pH 7.0. This analysis suggests that C8 challenge causes intracellular acidification and membrane damage. Escherichia coli MG1655 was grown to midlog (OD550 ~0.8) with or without 10 mM octanoic acid (pH=7.0) and the RNA was harvested and prepared for Affymetrix Microarray analysis.