Resuscitation-Promoting Factor Accelerates Enrichment of Highly Active Tetrachloroethene/Polychlorinated Biphenyl-Dechlorinating Cultures

The resuscitation promoting factor (Rpf) of Micrococcus luteus has been reported to resuscitate and stimulate the growth of functional microorganisms that are involved in the aerobic degradation of polychlorinated biphenyls (PCBs). However, few studies have been conducted to investigate the role of Rpf on anaerobic microbial populations. The anaerobic bioremediation of polychlorinated biphenyls (PCBs) is largely impeded by difficulties in massively enriching PCB dechlorinators in short periods of time. Tetrachloroethene (PCE) is often utilized as an alternative electron acceptor to preenrich PCB-dechlorinating bacteria. In this study, resuscitation promoting factor (Rpf) was used as an additive to enhance the enrichment of the microbial communities involved in PCE/PCBs dechlorination. The results indicated that Rpf accelerates PCE dechlorination 3.8 to 5.4 times faster than control cultures. In Aroclor 1260-fed cultures, the amendment of Rpf enables significantly more rapid and extensive dechlorination of PCBs. The residual high-chlorinated PCB congeners (>= 5 Cl atoms) accounted for 36.7% and 59.8% in the Rpf-amended cultures and in the corresponding controls, respectively. This improvement was mainly attributed to the enhanced activity of the removal of meta-chlorines (47.7 mol % versus 14.7 mol %), which did not appear to affect dechlorination pathways. The dechlorinators, including Dehalococcoides in Chloroflexi and Desulfitobacterium in Firmicutes, were greatly enriched via Rpf amendment. The abundance of nondechlorinating populations, including Methanosarcina, Desulfovibrio, and Bacteroides, was also greatly enhanced via Rpf amendment. These results suggest that Rpf serves as an effective additive for the rapid enrichment of active dechlorinating cultures so as to provide a new approach by which to massively cultivate bioinoculants for accelerated in situ anaerobic bioremediation.IMPORTANCE The resuscitation promoting factor (Rpf) of Micrococcus luteus has been reported to resuscitate and stimulate the growth of functional microorganisms that are involved in the aerobic degradation of polychlorinated biphenyls (PCBs). However, few studies have been conducted to investigate the role of Rpf on anaerobic microbial populations. In this study, the enhancement of Rpf on the anaerobic microbial dechlorination of PCE/PCBs was discovered. Additionally, the Rpf-responsive populations underlying the enhanced dechlorination were uncovered. This report reveals the rapid enrichment of active dechlorinating cultures via Rpf amendment, and this sheds light on massively enriching PCB dechlorinators in short periods of time. The enhanced in situ anaerobic bioremediation of PCBs could be expected by supplementing Rpf.

Automated summary

This study discovered the enhancement of Rpf on the anaerobic microbial dechlorination of PCE/PCBs and uncovered the underlying Rpf-responsive populations. It reveals the possibility of rapidly enriching active dechlorinating cultures through Rpf amendment, providing a new approach for massively enriching PCB dechlorinators in short periods of time.