Willmann Anna, Trautmann Anna-Lena, Kushmaro Ariel, Tiehm Andreas
Department of Water Microbiology TZW: DVGW-Technologiezentrum Wasser, Karlsruher Straße 84, 76139 Karlsruhe, Germany.
Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben Gurion University, Israel.
Heliyon. 2023 Feb 6;9(2):e13485. doi: 10.1016/j.heliyon.2023.e13485. eCollection 2023 Feb.
Trichloroethene (TCE) is one of the most prevalent contaminants in groundwater pollution worldwide. Aerobic-metabolic degradation of TCE has only recently been discovered at one field site. It has significant advantages over aerobic co-metabolism because no auxiliary substrates are required, and the oxygen demand is considerably lower. This study investigated the intrinsic degradation potential as well as the stimulation potential by bioaugmentation in microcosm experiments with groundwater from seven different sites contaminated with chloroethenes. An enrichment culture metabolizing TCE aerobically served as inoculum. The groundwater samples were inoculated with liquid culture in mineral salts medium as well as with immobilized culture on silica sand. Additionally, some samples were inoculated with groundwater from the site where the enrichment culture originated. The microcosms without inoculum proved the occurrence of aerobic TCE-metabolizing bacteria stimulated by the supply of oxygen in 54% of the groundwater samples. TCE degradation started in most cases after adaptation times of up to 92 d. The doubling time of 24 d indicated comparatively slow growth of the aerobic TCE degrading microorganisms. Bioaugmentation triggered or accelerated TCE-degradation in all microcosms with chlorothene concentrations below 100 mg L. All inoculation strategies (liquid and immobilized enrichment culture or addition of groundwater from the active field site) were successful. Our study demonstrates that aerobic-metabolic TCE degradation can occur and be stimulated across a broad hydrogeologic spectrum and should be considered as a viable option for groundwater remediation at TCE-contaminated sites.
三氯乙烯（TCE）是全球地下水污染中最普遍的污染物之一。直到最近才在一个现场发现了TCE的好氧代谢降解现象。与好氧共代谢相比，它具有显著优势，因为不需要辅助底物，且需氧量大大降低。本研究通过对七个受氯乙烯污染的不同地点的地下水进行微观实验，研究了其内在降解潜力以及生物强化的刺激潜力。一种好氧代谢TCE的富集培养物用作接种物。地下水样品接种了矿物盐培养基中的液体培养物以及硅砂上的固定化培养物。此外，一些样品接种了来自富集培养物来源地点的地下水。未接种的微观实验证明，在54%的地下水样品中，通过供应氧气刺激了好氧TCE代谢细菌的出现。在大多数情况下，TCE降解在长达92天的适应期后开始。24天的倍增时间表明好氧TCE降解微生物的生长相对缓慢。生物强化在所有氯乙烯浓度低于100mg/L的微观实验中引发或加速了TCE降解。所有接种策略（液体和固定化富集培养物或添加来自活跃现场的地下水）均成功。我们的研究表明，好氧代谢TCE降解可以在广泛的水文地质范围内发生并受到刺激，应被视为TCE污染场地地下水修复的可行选择。
