Table 1 Previous reports of the role of OmpF and FadL in tolerance of membrane-damaging compounds

OmpF, outer membrane porin F

 C₈–C₁₄ fatty acids

Production of ~1 g/L fatty acids during growth in LB with glycerol, 37 °C

Deletion of ompF from a derivative of MG1655 had no impact on cell viability or membrane integrity

[26]

 Octanoic acid (C8)

Challenge with up to 20 mM C8 in minimal media with glucose, tryptone and yeast extract at pH 7.0 and 37 °C

Deletion of ompF from BW25113 decreased sensitivity to C8, and increased expression of ompF increased sensitivity to C8. Sensitivity was assessed via the maximum OD. Deletion of ompF decreased the magnitude of intracellular acidification

[32]

 Phenylpropanoids

Challenge with 1 g/L rutin, naringenin or resveratrol in M9 medium with casamino acids and glucose at 30 °C

Increased expression of ompF in BL21 increased the maximum specific growth rate during challenge. Decreased growth rate during challenge was observed when ompF expression was decreased

[33]

FadL, long-chain fatty acid outer membrane porin

 C₈–C₁₄ fatty acids

Production of ~1 g/L fatty acids during growth in LB with glycerol at 37 °C

Deletion of fadL from a derivative of MG1655 had no impact on cell viability or membrane integrity

[26]

 Palmitic and ω-hydroxy palmitic acids

Addition of 1 mM palmitic acid in potassium phosphate buffer with glucose or glycerol, 30 °C

Increased expression of fadL increased conversion of palmitic acid to ω-hydroxy palmitic acid. The increase was smaller in the presence of glycerol than glucose

[34]

 Phenol

Challenge with phenol at 50–75% of the MIC in LB at 37 °C

Deletion of fadL from BW25113 had no impact on survival

[37]

 Octane

Addition of ~20 vol% octane in LB at 37 °C

Deletion of fadL from a BW25113 derivative abolished conversion of octane to octanol, octanal and octanoic acid

[35]

 Hexane

Challenge with 10 vol% hexane in LB at 37 °C

Deletion of fadL from BW25113 increased survival, as assessed by OD

[35]

 Phenylpropanoids

Challenge with 1 g/L rutin, naringenin or resveratrol in minimal medium with casamino acids and glucose at 30 °C

Increased expression of fadL in BL21 increased the maximum specific growth rate during challenge. Decreased growth rate during challenge was observed when fadL expression was decreased

[33]