School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou 510006, China.
China State Science Dingshi Environmental Engineering Co., Ltd., Beijing 100102, China.
Environ Sci Technol. 2023 Nov 14;57(45):17338-17352. doi: 10.1021/acs.est.3c05932. Epub 2023 Oct 30.
Organohalide-respiring bacteria (OHRB)-mediated reductive dehalogenation is promising in bioremediation of chloroethene-contaminated sites. The bioremediation efficiency of this approach is largely determined by the successful colonization of fastidious OHRB, which is highly dependent on the presence of proper growth niches and microbial interactions. In this study, based on two ecological principles (i.e., Priority Effects and Coexistence Theory), three strategies were developed to enhance niche colonization of OHRB, which were tested both in laboratory experiments and field applications: (i) preinoculation of a niche-preparing culture (NPC, being mainly constituted of fermenting bacteria and methanogens); (ii) staggered fermentation; and (iii) increased inoculation of CE40 (a -containing tetrachloroethene-to-ethene dechlorinating enrichment culture). Batch experimental results show significantly higher dechlorination efficiencies, as well as lower concentrations of volatile fatty acids (VFAs) and methane, in experimental sets with staggered fermentation and niche-preconditioning with NPC for 4 days (CE40_NPC-4) relative to control sets. Accordingly, a comparatively higher abundance of as major OHRB, together with a lower abundance of fermenting bacteria and methanogens, was observed in CE40_NPC-4 with staggered fermentation, which indicated the balanced syntrophic and competitive interactions between OHRB and other populations for the efficient dechlorination. Further experiments with microbial source tracking analyses suggested enhanced colonization of OHRB by increasing the inoculation ratio of CE40. The optimized conditions for enhanced colonization of OHRB were successfully employed for field bioremediation of trichloroethene (TCE, 0.3-1.4 mM)- and vinyl chloride (VC, ∼0.04 mM)-contaminated sites, resulting in 96.6% TCE and 99.7% VC dechlorination to ethene within 5 and 3 months, respectively. This study provides ecological principles-guided strategies for efficient bioremediation of chloroethene-contaminated sites, which may be also employed for removal of other emerging organohalide pollutants.
有机卤化物呼吸细菌（OHRB）介导的还原脱卤作用在氯代烯烃污染场地的生物修复中很有前景。这种方法的生物修复效率在很大程度上取决于对挑剔的 OHRB 的成功定植，而这高度依赖于适当的生长小生境和微生物相互作用的存在。在这项研究中，基于两个生态原则（即优先效应和共存理论），开发了三种策略来增强 OHRB 的小生境定殖，这些策略在实验室实验和现场应用中都进行了测试：（i）接种前培养（NPC，主要由发酵细菌和产甲烷菌组成）；（ii）交错发酵；和（iii）增加含有 CE40（四氯代乙稀到乙烯脱氯的富集培养物）的接种。批实验结果表明，与对照组相比，具有交错发酵和 NPC 预处理 4 天（CE40_NPC-4）的实验组的脱氯效率显著提高，挥发性脂肪酸（VFAs）和甲烷的浓度也更低。相应地，在具有交错发酵和 NPC 预处理 4 天（CE40_NPC-4）的实验组中，发现作为主要 OHRB 的 丰度较高，而发酵细菌和产甲烷菌的丰度较低，这表明 OHRB 与其他种群之间的共生和竞争相互作用是平衡的，有利于高效脱氯。进一步的微生物来源追踪分析实验表明，通过增加 CE40 的接种比例，可以增强 OHRB 的定植。成功地将增强 OHRB 定殖的优化条件应用于三氯乙烯（TCE，0.3-1.4mM）和氯乙烯（VC，∼0.04mM）污染场地的现场生物修复，分别在 5 个月和 3 个月内将 TCE 和 VC 脱氯至乙烯，脱氯率分别达到 96.6%和 99.7%。本研究为氯代烯烃污染场地的高效生物修复提供了基于生态原则的策略，也可用于去除其他新兴的有机卤化物污染物。
