Continuous cultures of Pseudomonas putida mt-2 overcome catabolic function loss under real case operating conditions.
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.
Muñoz
Raúl
R
Department of Chemical Engineering and Environmental Technology, Valladolid University, Paseo del Prado de Magdalena, s/n, Valladolid, Spain.
Hernández
María
M
Segura
Ana
A
Gouveia
Joao
J
Rojas
Antonia
A
Ramos
Juan Luis
JL
Villaverde
Santiago
S
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
D014050:Toluene; D050557:Catechol 2,3-Dioxygenase