From trash to treasure: Microbial conversion of palladium contaminants into valuable Pd nanoparticles by Bacillus thuringiensis Y9

The Pd (II) Reduction Mechanisms in Bacillus megaterium Y-4 Revealed by Proteomic Analysis

“…As depicted in Figure 1 B,D and Table S3 , binding energies centered at 340.0–340.7 eV and 334.7–335.4 eV were observed, which was attributed to Pd 3d/2 and Pd 5d/2 of Pd (0). In addition, binding energies centered at 342.3–343.4 eV and 337.1–338.1 eV were observed, which was ascribed to Pd 3d/2 and Pd 5d/2 of Pd (II) [ 18 ]. The presence of Pd (0) after B. megaterium Y treatment demonstrates the conversion of palladium under the experimental conditions.…”

“…Based on the data accumulated in this study, B. megaterium Y-4 may utilize endogenous electron donors (such as NAD(P)H) or reductase to provide electrons for Pd (II) reduction. Endogenous electron mediators (quinones and flavins) may further enhance Pd (II) reduction [ 18 , 25 ]. The ribosome-relevant proteins can maintain the translation, protein metabolism, and RNA process.…”

“…The role of the NADH dehydrogenases and hydrogenases (especially HyaB) of Shewanella oneidensis MR-1 was demonstrated to be responsible for the formation of bio-Pd on the outer membrane and in the periplasmic space, respectively [ 17 ]. Transcriptomic analyses revealed that the genes encoding NADH–quinone oxidoreductase, dehydrogenases, cytochrome c reductase, cytochrome c oxidase, the quinone cycle, and ribE in Bacillus thuringiensis Y9 have a strong positive relationship with palladium reduction [ 18 ]. The genes encoding oxidoreductase, metabolic enzymes, and cell-surface proteins were mainly identified to be responsible for the reduction of Pd (II) [ 19 ].…”