Division Soil and Water Management, Katholieke Universiteit Leuven, Kasteelpark Arenberg 20, 3001 Heverlee, Belgium.
Water Res. 2010 Jan;44(1):331-9. doi: 10.1016/j.watres.2009.09.033. Epub 2009 Sep 17.
The reductive dechlorination of trichloroethene (TCE) in a TCE source zone can be self-inhibited by TCE toxicity. A study was set up to examine the toxicity of TCE in terms of species specific degradation kinetics and microbial growth and to evaluate models that describe this self-inhibition. A batch experiment was performed using the TCE dechlorinating KB-1 culture at initial TCE concentrations ranging from 0.04mM to saturation (8.4mM). Biodegradation activity was highest at 0.3mM TCE and no activity was found at concentrations from 4 to 8mM. Species specific TCE and cis-DCE (cis-dichloroethene) degradation rates and Dehalococcoides numbers were modeled with Monod kinetics combined with either Haldane inhibition or a log-logistic dose-response inhibition on these rates. The log-logistic toxicity model appeared the most appropriate model and predicts that the species specific degradation activities are reduced by a factor 2 at about 1mM TCE, respectively cis-DCE. However, the model showed that the inhibitive effects on the time for TCE to ethene degradation are a complex function of degradation kinetics and the initial cell densities of the dechlorinating species. Our analysis suggests that the self-inhibition on biodegradation cannot be predicted by a single concentration threshold without information on the cell densities.
三氯乙烯 (TCE) 在 TCE 污染源中的还原脱氯作用可能会受到 TCE 毒性的自我抑制。本研究旨在通过特定物种的降解动力学和微生物生长来考察 TCE 的毒性，并评估描述这种自我抑制的模型。在初始 TCE 浓度范围为 0.04mM 至饱和（8.4mM）的情况下，使用 TCE 脱氯 KB-1 培养物进行了批处理实验。在 0.3mM TCE 时，生物降解活性最高，而在 4 至 8mM 浓度时则没有发现活性。使用 Monod 动力学结合 Haldane 抑制或这些速率的对数逻辑剂量反应抑制对特定物种的 TCE 和顺式-DCE（顺式-二氯乙烯）降解率和 Dehalococcoides 数量进行了建模。对数逻辑毒性模型似乎是最合适的模型，并且预测特定物种的降解活性在约 1mM TCE 时分别降低了 2 倍，顺式-DCE。然而，该模型表明，对 TCE 到乙烯降解所需时间的抑制作用是降解动力学和脱氯物种初始细胞密度的复杂函数。我们的分析表明，没有关于细胞密度的信息，单凭单一浓度阈值无法预测生物降解的自我抑制。
