Department of Chemical Engineering and Environmental Technology, University of Valladolid, Paseo del Prado de la Magdalena s/n, Valladolid E-47005, Spain.
Water Sci Technol. 2009;60(9):2391-8. doi: 10.2166/wst.2009.681.
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.
在无菌悬浮生长生物反应器中，以恒化器的方式运行，分别用野生型菌株、缺乏 pGRT1 质粒的突变株（P. putida DOT-TIE-100）和修饰后的缺乏编码 ttgGHI 溶剂外排泵基因的 pGRT1 质粒的突变株（P. putida DOT-TIE-28）独立接种，研究了质粒 pGRT1 和溶剂外排泵 ttgGHI 在 Pseudomonas putida DOT-T1E 培养物中降解甲苯的作用。在 4 g tol m(-3)和稀释率（D）为 0.1 h(-1)的情况下，所有测试菌株的过程性能相似。然而，在 10 g tol m(-3)和 D 为 0.2 h(-1)的条件下，与野生型和 P. putida DOT-T1E-28 培养物（483-498 g m(-3) h(-1)）相比，P. putida DOT-T1E-100 培养物中的甲苯 EC（285 g m(-3) h(-1)）要低得多，这表明支持这种优越的过程性能的机制除了 ttgGHI 外排泵的溶剂外排之外还有其他机制。最后，分析的质粒 pGRT1 表现出对甲苯有害影响的显著稳定性，无论测试的菌株或甲苯负荷如何。
