Improving E. coli organic solvent tolerance by 1,4-dihydroxy-2-naphthoic acid.

Area of Science:

• Microbiology
• Biotechnology
• Biochemistry

Background:

• Enhancing bacterial organic solvent tolerance is crucial for industrial bioproduction.
• Escherichia coli possesses intrinsic tolerance mechanisms, including the AcrAB-TolC efflux pump.

Purpose of the Study:

• To investigate the effect of 1,4-dihydroxy-2-naphthoic acid (DHNA) on the organic solvent tolerance of Escherichia coli.
• To elucidate the molecular mechanisms underlying DHNA-mediated enhancement of solvent tolerance.

Main Methods:

• Assessing organic solvent tolerance in wild-type and mutant E. coli strains with and without DHNA.
• Measuring the expression levels of the AcrAB-TolC pump components.
• Evaluating the promoter activities of key regulatory genes (marA, soxS).

Main Results:

• DHNA significantly increased organic solvent tolerance in E. coli.
• DHNA treatment led to increased expression of the AcrAB-TolC efflux pump.
• DHNA's effect was dependent on the MarRAB and SoxRS regulatory systems, as indicated by mutant studies and promoter activity assays.

Conclusions:

• DHNA enhances bacterial organic solvent tolerance by inducing the AcrAB-TolC multidrug efflux pump.
• The induction mechanism involves the activation of both the marRAB and soxRS regulatory pathways.
• DHNA represents a promising prebiotic for improving bacterial performance in solvent-exposed bioprocesses.