Tiehm Andreas, Schmidt Kathrin R, Pfeifer Brigitte, Heidinger Michael, Ertl Siegmund
Department of Environmental Biotechnology, Water Technology Center, Karlsruher Street 84, 76139 Karlsruhe, Germany.
Water Res. 2008 May;42(10-11):2431-8. doi: 10.1016/j.watres.2008.01.029. Epub 2008 Feb 3.
Assessing changes in the isotopic signature of contaminants is a promising new tool to monitor microbial degradation processes. In this study, chloroethene degradation was proven by depletion of chloroethenes, formation of chloride, increase in protein content and stable carbon isotope fractionation. Aerobic degradation of vinyl chloride (VC) was found to proceed metabolically, with degradation rates of 0.48 and 0.29 d(-1); and growth yields of 9.7 and 6.4 g of protein/mol of VC at room and groundwater temperature, respectively. Cis-1,2-dichloroethene (cDCE) was degraded cometabolically under aerobic conditions when VC was provided as growth substrate. Aerobic degradation was associated with significant stable carbon isotope fractionation, with enrichment factors ranging from -5.4+/-0.4 per thousand for metabolic degradation of VC to -9.8+/-1.7 per thousand for cometabolic degradation of cDCE. Thus, it was demonstrated that stable carbon isotope fractionation is suitable for assessing aerobic chloroethene degradation, which can contribute significantly to site remediation.
评估污染物同位素特征的变化是监测微生物降解过程的一种很有前景的新工具。在本研究中，氯乙烯的降解通过氯乙烯的消耗、氯离子的形成、蛋白质含量的增加以及稳定碳同位素分馏得以证实。发现氯乙烯（VC）的好氧降解以代谢方式进行，降解速率分别为0.48和0.29 d(-1)；在室温和地下水温度下，生长产率分别为每摩尔VC产生9.7和6.4克蛋白质。当以VC作为生长底物时，顺式1,2 - 二氯乙烯（cDCE）在好氧条件下通过共代谢降解。好氧降解与显著的稳定碳同位素分馏相关，富集因子范围从VC代谢降解的-5.4±0.4‰到cDCE共代谢降解的-9.8±1.7‰。因此，证明了稳定碳同位素分馏适用于评估好氧氯乙烯降解，这对场地修复有显著贡献。
