Metatranscriptomic insights into resuscitation-promoting factor-enhanced aerobic biodegradation of perfluorooctanoic acid

Rpf significantly enhances aerobic biodegradation and defluorination of PFOA • Core PFOA biotransformation pathways remain unchanged by Rpf • Defluorination-associated functions are transcriptionally activated • Transcriptionally active PFOA-degrading taxa expanded after Rpf amendment • Rpf upregulates key enzymes across multiple PFOA biodegradation pathways Biodegradation of perfluorooctanoic acid (PFOA) represents a promising strategy for sustainable remediation of per- and polyfluoroalkyl substances (PFAS), yet its efficiency is often constrained by low microbial activity and the prevalence of viable but non-culturable (VBNC) degraders. This study investigated whether the resuscitation-promoting factor (Rpf) from Micrococcus luteus could enhance aerobic PFOA biodegradation and elucidated the underlying microbial mechanisms. An enriched culture (PG5) dominated by Pseudomonadota was established and achieved 55.5% degradation of 10 mg/L PFOA within 48 h, accompanied by fluoride release. Rpf supplementation significantly enhanced PFOA degradation, increasing removal to 68.1% at 10 mg/L PFOA (12.9% increase) and 35.8% at 100 mg/L PFOA (5.2% increase), with corresponding increases in defluorination. Pathway analyses demonstrated that Rpf accelerated degradation without altering the core transformation pathway involving decarboxylation, hydrolytic elimination, and hydrogen exchange. Metatranscriptomic profiling revealed extensive transcriptional reprogramming following Rpf amendment, including the upregulation of genes encoding haloacid dehalogenases, enoyl-CoA hydratase, haloalkane dehalogenase, and fluoride exporters involved in PFOA biotransformation. Genes associated with VBNC-state regulation were also induced, suggesting the potential for reactivation of VBNC populations. Rpf further expanded the transcriptionally active community, with Hyphomicrobium , Aquamicrobium , Pusillimonas , and Chryseobacterium emerging as key functional taxa associated with defluorination and downstream transformation processes. These results demonstrate that Rpf enhances PFOA biodegradation by stimulating functional gene expression and activating diverse microbial populations, providing mechanistic insight into Rpf-mediated enhancement of PFAS biodegradation and highlighting a promising strategy for PFAS bioremediation. Download: Download high-res image (143KB) Download: Download full-size image