Departament d'Enginyeria Química, Biològica i Ambiental, Universitat Autònoma de Barcelona (UAB), Bellaterra, Barcelona, Spain.
Institut de Química Avançada de Catalunya (IQAC) CSIC, Barcelona, Spain.
J Hazard Mater. 2017 Jun 5;331:218-225. doi: 10.1016/j.jhazmat.2017.02.043. Epub 2017 Feb 27.
1,1,2-Trichloroethane (1,1,2-TCA) is a non-flammable organic solvent and common environmental contaminant in groundwater. Organohalide-respiring bacteria are key microorganisms to remediate 1,1,2-TCA because they can gain metabolic energy during its dechlorination under anaerobic conditions. However, all current isolates produce hazardous end products such as vinyl chloride, monochloroethane or 1,2-dichloroethane that accumulate in the medium. Here, we constructed a syntrophic co-culture of Dehalogenimonas and Dehalococcoides mccartyi strains to achieve complete detoxification of 1,1,2-TCA to ethene. In this co-culture, Dehalogenimonas transformed 1,1,2-TCA via dihaloelimination to vinyl chloride, whereas Dehalococcoides reduced vinyl chloride via hydrogenolysis to ethene. Molasses, pyruvate, and lactate supported full dechlorination of 1,1,2-TCA in serum bottle co-cultures. Scale up of the cultivation to a 5-L bioreactor operating for 76d in fed-batch mode was successful with pyruvate as substrate. This synthetic combination of bacteria with known complementary metabolic capabilities demonstrates the potential environmental relevance of microbial cooperation to detoxify 1,1,2-TCA.
1,1,2-三氯乙烷（1,1,2-TCA）是一种不可燃的有机溶剂，也是地下水环境中的常见污染物。能够在厌氧条件下通过脱氯过程获取代谢能量的有机卤代物呼吸细菌，是修复 1,1,2-TCA 的关键微生物。然而，所有目前的分离株都会产生危险的终产物，如氯乙烯、一氯乙烷或 1,2-二氯乙烷，这些终产物会在培养基中积累。在这里，我们构建了一种脱硫单胞菌和脱硫球菌的共培养物，以实现 1,1,2-TCA 向乙烯的完全解毒。在这种共培养物中，脱硫单胞菌通过二卤消除作用将 1,1,2-TCA 转化为氯乙烯，而脱硫球菌通过氢解作用将氯乙烯还原为乙烯。糖蜜、丙酮酸盐和乳酸盐支持 1,1,2-TCA 在血清瓶共培养物中的完全脱氯。以丙酮酸盐为底物，成功地将培养规模扩大到 5-L 生物反应器中，并以分批进料模式运行 76d。这种具有已知互补代谢能力的细菌的合成组合，展示了微生物合作解毒 1,1,2-TCA 的潜在环境相关性。
