Muñoz Raúl, Hernández María, Segura Ana, Gouveia Joao, Rojas Antonia, Ramos Juan Luis, Villaverde Santiago
Department of Chemical Engineering and Environmental Technology, Valladolid University, Paseo del Prado de Magdalena, s/n, Valladolid, Spain.
Appl Microbiol Biotechnol. 2009 May;83(1):189-98. doi: 10.1007/s00253-009-1928-5. Epub 2009 Mar 10.
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.
在实际工况下运行的恒化器生物反应器中，研究了恶臭假单胞菌mt - 2培养物的长期性能和稳定性。该菌株对甲苯敏感，在原型质粒pWW0中携带负责甲苯生物降解的基因。该过程在稀释率为0.1 h⁻¹的条件下运行，甲苯负荷率分别为259±23和801±78 g m⁻³ h⁻¹（入口甲苯浓度分别为3.5和10.9 g m⁻³）。尽管甲苯及其降解中间体具有有害影响，但这种敏感的恶臭假单胞菌培养物的表型在第4天从95%的甲苯抗性（Tol⁻）群体迅速恢复，从第13天起恢复到约100%的甲苯敏感（Tol⁺）细胞，在3.5 g甲苯每立方米时维持232±10 g m⁻³ h⁻¹的去除能力，在10.9 g甲苯每立方米时维持377±13 g m⁻³ h⁻¹的去除能力，这与在相同实验条件下高度耐受的菌株如恶臭假单胞菌DOT T1E和恶臭假单胞菌F1所达到的去除能力相当。仅鉴定出一种甲苯抗性（Tol⁻）变体，其携带一个具有38.5 kb缺失的类TOL质粒（包含甲苯生物降解的上游和间位操纵子）。
