Active efflux of organic solvents by Pseudomonas putida S12 is induced by solvents.

Induction of the membrane-associated organic solvent efflux system SrpABC of Pseudomonas putida S12 was examined by cloning a 312-bp DNA fragment, containing the srp promoter, in the broad-host-range reporter vector pKRZ-1. Compounds that are capable of inducing expression of the srpABC genes include aromatic and aliphatic solvents and alcohols. General stress conditions such as pH, temperature, NaCl, or the presence of organic acids did not induce srp transcription. Although the solvent efflux pump in P. putida S12 is a member of the resistance-nodulation-cell division family of transporters, the srpABC genes were not induced by antibiotics or heavy metals.