Addressing the role of the extrusion pump-bearing pGRT1 plasmid in toluene biodegradation by Pseudomonas putida DOT-T1E under real case scenarios.
The role of both the plasmid pGRT1 and the solvent extrusion pump ttgGHI during toluene biodegradation in Pseudomonas putida DOT-T1E cultures was investigated in a sterile suspended growth bioreactor operated as chemostat and inoculated independently with a wild type strain, a mutant lacking the pGRT1 plasmid (P. putida DOT-TIE-100), and a mutant with a modified pGRT1 plasmid lacking the genes encoding the ttgGHI solvent efflux pump (P. putida DOT-TIE-28). A similar process performance was recorded in all tested strains at 4 g tol m(-3) and dilution rates (D) of 0.1 h(-1). However, operation at 10 g tol m(-3) and D of 0.2 h(-1) revealed a much lower toluene EC (285 g m(-3) h(-1)) in P. putida DOT-T1E-100 cultures when compared to wild type and P. putida DOT-T1E-28 cultures (483-498 g m(-3) h(-1)), which suggests that other mechanisms rather than solvent extrusion by the ttgGHI efflux pump supported this superior process performance. Finally, the plasmid pGRT1 analysed exhibited a remarkable stability towards toluene harmful mediated effects, regardless the strain or toluene loading tested.
Hernandez
M
M
Department of Chemical Engineering and Environmental Technology, University of Valladolid, Paseo del Prado de la Magdalena s/n, Valladolid E-47005, Spain. hergama@iq.uva.es
Gouveia
J
J
Segura
A
A
Muñoz
R
R
Villaverde
S
S
D001673:Biodegradation, Environmental; D018533:Biomass; D019149:Bioreactors; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D010957:Plasmids; D016958:Pseudomonas putida / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D014050:Toluene / Q000737:chemistry / Q000378:metabolism*
D002352:Carrier Proteins; D014050:Toluene