title: Continuous cultures of Pseudomonas putida mt-2 overcome catabolic function loss under real case operating conditions.
abstract: The long-term performance and stability of Pseudomonas putida mt-2 cultures, a toluene-sensitive strain harboring the genes responsible for toluene biodegradation in the archetypal plasmid pWW0, was investigated in a chemostat bioreactor functioning under real case operating conditions. The process was operated at a dilution rate of 0.1 h(-1) under toluene loading rates of 259 +/- 23 and 801 +/- 78 g m(-3) h(-1) (inlet toluene concentrations of 3.5 and 10.9 g m(-3), respectively). Despite the deleterious effects of toluene and its degradation intermediates, the phenotype of this sensitive P. putida culture rapidly recovered from a 95% Tol(-) population at day 4 to approx. 100% Tol(+) cells from day 13 onward, sustaining elimination capacities of 232 +/- 10 g m(-3) h(-1) at 3.5 g Tol m(-3) and 377 +/- 13 g m(-3) h(-1) at 10.9 g Tol m(-3), which were comparable to those achieved by highly tolerant strains such as P. putida DOT T1E and P. putida F1 under identical experimental conditions. Only one type of Tol(-) variant, harboring a TOL-like plasmid with a 38.5 kb deletion (containing the upper and meta operons for toluene biodegradation), was identified.
authors.affiliation: Department of Chemical Engineering and Environmental Technology, Valladolid University, Paseo del Prado de Magdalena, s/n, Valladolid, Spain.
authors.forename: Raúl
authors.initials: R
authors.lastname: Muñoz
authors.forename: María
authors.initials: M
authors.lastname: Hernández
authors.forename: Ana
authors.initials: A
authors.lastname: Segura
authors.forename: Joao
authors.initials: J
authors.lastname: Gouveia
authors.forename: Antonia
authors.initials: A
authors.lastname: Rojas
authors.forename: Juan Luis
authors.initials: JL
authors.lastname: Ramos
authors.forename: Santiago
authors.initials: S
authors.lastname: Villaverde
mesh_terms: D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D001711:Biotransformation; D050557:Catechol 2,3-Dioxygenase / Q000378:metabolism; D042822:Genomic Instability; D010101:Oxygen Consumption; D010957:Plasmids; D016958:Pseudomonas putida / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D014050:Toluene / Q000378:metabolism* / Q000633:toxicity
chemical_list: D014050:Toluene; D050557:Catechol 2,3-Dioxygenase