Supplementing resuscitation-promoting factor (Rpf) enhanced biodegradation of polychlorinated biphenyls (PCBs) by Rhodococcus biphenylivorans strain TG9T
2020
Ye, Zhe | Li, Hongxuan | Jia, Yangyang | Fan, Jiahui | Wan, Jixing | Guo, Li | Su, Xiaomei | Zhang, Yu | Wu, Weimin | Shen, Chaofeng
The biodegradation of polychlorinated biphenyls (PCBs) occurs slowly when the degrading bacteria enter a low activity state, such as a viable but nonculturable (VBNC) state, under unfavorable environmental conditions. The introduction of resuscitation-promoting factor (Rpf) can re-activate VBNC bacteria. This study tested the feasibility of enhancing PCB biodegradation via supplementing Rpf in liquid culture and soil microcosms inoculated with Rhodococcus biphenylivorans strain TG9ᵀ. Exogenous Rpf resuscitated TG9ᵀ cells that had previously entered the VBNC state after 90 d of nutrient starvation, resulting in the significantly enhanced degradation of PCB by 24.3% over 60 h in liquid medium that originally contained 50 mg L⁻¹ Aroclor 1242. In soil microcosms containing 50 mg kg⁻¹ Aroclor 1242 and inoculated with VBNC TG9ᵀ cells, after 49 d of supplementation with Rpf, degradation efficiency of PCB reached 34.2%, which was significantly higher than the control. Our results confirmed that exogenous Rpf resuscitated VBNC TG9ᵀ cells by stimulating endogenous expression of rpf gene orthologs. The enhanced PCB-degrading capability was likely due to the increased cell numbers and the strong expression of PCB catabolic genes. This study demonstrated the role of Rpf in enhancing PCB degradation via resuscitating PCB-degrading bacteria, indicating a promising approach for the remediation of PCB contamination.
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