Pd0 FOF1-ATPase prone pump modulated-detoxification of oxytetracycline in Bacillus megaterium Y-4

Bio-remediation are low-cost and environmentally friendly, but microbial enzymes tend to lose their activity when treated antibiotic contaminants due to its high toxicity. In this study, Bacillus megaterium Y-4 was demonstrated to in situ synthesize Pd 0 @cells, and detoxify oxytetracycline (OTC) through enhancing electron transport chain via Pd 0 -dependent F O F 1 -ATPase (proton pumps). Toxicity analyses showed that increasing Pd 0 loading significantly reduced acute and chronic bio-toxicity as well as ecological risk of OTC effluent, as evidenced by the promoting cellular response to oxidative stress with increasing enzymes GSH-Px and IDH activities (4.24 and 1.20-fold). Electrochemical (I-t, LSV, DPV and EDC) showed that the incorporated bio-Pd 0 mainly promoted FDH/Hase-based short chain (gradually took precedence over CoQ-based long chain), diverting OTC extracellular degradation to markedly detoxify OTC to cell. Inhibition (DCCD and TBA) assays and structural equation modelling indicated that bio-Pd 0 upregulated ATP and NADH synthesis. It also acted as transmembrane F O F 1 -ATPase proton pump, which enabled the backward of protons out of the restriction of PMF , eventually maximizing the energy utilization. This study sheds new insights into the detoxification of antibiotics by bio-nanoparticles through proton transmembrane transfer/redistribution.