Muñoz R, Díaz L F, Bordel S, Villaverde S
Department of Chemical Engineering and Environmental Technology, University of Valladolid, Paseo del Prado de la Magdalena s/n, Valladolid, Spain.
Chemosphere. 2007 Jun;68(2):244-52. doi: 10.1016/j.chemosphere.2007.01.016. Epub 2007 Feb 21.
The influence of benzene concentration on the specific growth rate (mu), CO(2) and metabolite production, and cellular energetic content (i.e., ATP content), during benzene biodegradation by Pseudomonas putida F1 was investigated. Within the concentration range tested (5-130mg benzene l(-1)) the mu, the specific CO(2) production, and the ATP content remained constant at 0.42-0.48h(-1), 1.86+/-0.21g CO(2) g(-1) biomass, and 5.3+/-0.4x10(-6)mol ATP g(-1) biomass, respectively. Catechol accumulated during process start-up at all tested concentrations. Catechol specific production increased with increasing benzene inlet concentrations. This confirms that the transformation of this intermediate was the limiting step during benzene degradation. It was shown that catechol inhibited both the conversion of benzene to catechol and its further transformation. In addition, catechol concentrations higher than 10mgl(-1) significantly decreased both benzene and catechol associated respiration, confirming the highly inhibitory effect of this intermediate. This inhibitory threshold concentration was approximately two orders of magnitude lower than the concentrations present in the culture medium during process start-up, suggesting that cellular activity was always far below its maximum. Thus, due to its toxic and inhibitory nature and its tendency to accumulate at high benzene loading, catechol must be carefully monitored during process operation.
研究了苯浓度对恶臭假单胞菌F1降解苯过程中比生长速率（μ）、CO₂和代谢产物生成以及细胞能量含量（即ATP含量）的影响。在测试的浓度范围内（5 - 130mg苯L⁻¹），μ、比CO₂生成量和ATP含量分别保持恒定，为0.42 - 0.48h⁻¹、1.86 ± 0.21g CO₂ g⁻¹生物量和5.3 ± 0.4×10⁻⁶mol ATP g⁻¹生物量。在所有测试浓度下，邻苯二酚在过程启动阶段积累。邻苯二酚的比生成量随苯进口浓度的增加而增加。这证实了该中间体的转化是苯降解过程中的限速步骤。结果表明，邻苯二酚既抑制苯向邻苯二酚的转化，也抑制其进一步转化。此外，高于10mg L⁻¹的邻苯二酚浓度显著降低了与苯和邻苯二酚相关的呼吸作用，证实了该中间体具有高度抑制作用。该抑制阈值浓度比过程启动阶段培养基中的浓度低约两个数量级，表明细胞活性始终远低于其最大值。因此，由于邻苯二酚具有毒性和抑制性，且在高苯负荷下有积累的趋势，在过程运行中必须对其进行仔细监测。
