College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China.
Department of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
J Hazard Mater. 2024 Dec 5;480:136376. doi: 10.1016/j.jhazmat.2024.136376. Epub 2024 Oct 31.
The slow rate of anaerobic microbial dechlorination in natural environments limits the application of polychlorinated biphenyl (PCB) bioremediation. Anaerobic digested sludge (ADS), abundant in nutrients and microorganisms, could be an effective additive to improve microbial dechlorination. This research investigates the influence of ADS on Aroclor 1260 dechlorination performance, microbial community composition, and the abundance of functional genes. Moreover, further enrichment of organohalide-respiring bacteria (OHRB) was examined using tetrachloroethene (PCE) as the electron acceptor, followed by the serial dilution-to-extinction method in conjunction with resuscitation promoting factor (Rpf) supplementation. The results demonstrated that the addition of 5 g/L ADS achieved more extensive and efficient dechlorination of PCBs. ADS enhanced the removal of meta- and para-chlorine without significantly changing the dechlorination pathways. The abundances of dechlorinators, including Dehalobium and Dehalobacter within the Chloroflexi and Firmicutes phyla, as well as non-dechlorinators from the Desulfobacterota, Euryarchaeota, and Bacteroidetes phyla, were significantly increased with ADS amendment. Similarly, an increased abundance of bacteria, OHRB, reductive dehalogenase (RDase) genes, and archaeal 16S rRNA genes was observed. Additionally, obligate OHRB, such as Dehalobacter and Dehalobium, were further enriched. These findings indicate that ADS effectively enhances microbial reductive dechlorination and highlight the potential for enriching and isolating OHRB with Rpf.
在自然环境中，厌氧微生物的脱氯速度缓慢，限制了多氯联苯（PCB）生物修复的应用。厌氧消化污泥（ADS）富含营养物质和微生物，可作为一种有效的添加剂，以改善微生物脱氯性能。本研究考察了 ADS 对 Aroclor 1260 脱氯性能、微生物群落组成和功能基因丰度的影响。此外，还使用四氯乙烯（PCE）作为电子受体，通过连续稀释至灭绝法结合复苏促进因子（Rpf）补充，进一步富集了有机卤化物呼吸细菌（OHRB）。结果表明，添加 5 g/L ADS 可实现更广泛和更有效的 PCB 脱氯。ADS 增强了间位和对位氯的去除，而对脱氯途径没有显著影响。脱氯菌的丰度增加，包括 Chloroflexi 和 Firmicutes 门中的 Dehalobium 和 Dehalobacter，以及 Desulfobacterota、Euryarchaeota 和 Bacteroidetes 门中的非脱氯菌，随着 ADS 添加剂的增加而显著增加。同样，观察到细菌、OHRB、还原脱卤酶（RDase）基因和古菌 16S rRNA 基因的丰度增加。此外，还进一步富集了专性 OHRB，如 Dehalobacter 和 Dehalobium。这些发现表明 ADS 有效地增强了微生物的还原脱氯作用，并强调了使用 Rpf 富集和分离 OHRB 的潜力。
