ABSTRACT: Long-term effects and mechanisms of sulfur-modified nanoscale zero-valent iron in enhancing anaerobic treatment of highly toxic wastewater containing 2,4-dichlorophenol
Project description:The existence of light in various deep-sea environments has been well established. Our previous research found blue light promotes zero-valent sulfur (ZVS) production in Erythrobacter flavus 21-3, a bacterium isolated from the deep-sea cold seep. E. flavus 21-3 can convert thiosulfate to ZVS through a novel thiosulfate oxidation pathway comprising a thiosulfate dehydrogenase (TsdA) and two thiosulfohydrolases (SoxB). Using proteomic analysis, bacterial two-hybrid system and heterologous expression assays, we found that infrared light also promotes zero-valent sulfur (ZVS) production in E. flavus 21-3. The bacteriophytochrome (bphp) Ef2bphp-15570 autophosphorylated and activated GGDEF domain-containing protein D0Y83_RS00450 to produce c-di-GMP. Subsequently, the PilZ protein mPilZ-1753 bound to c-di-GMP and activated downstream sulfur oxidation pathways. During this process, polyphosphate kinase 2 (PPK2) affects the content of c-di-GMP by competing for GTP, thereby together c-di-GMP regulating ZVS production, as well as other metabolic processes in E. flavus 21-3. This study provides a novel insight into a deep-sea non-photosynthetic bacterium which sensing infrared light to regulate sulfur metabolism through a bacteriophytochrome photoreceptor, thus offering new understandings perspectives on microbial utilization of light energy.
Project description:Zero-valent sulfur (ZVS) distributes widely in the deep-sea cold seep, which is important immediate in the active sulfur cycle of cold seep. In our preview work, a novel ZVS formation pathway discovered in the deep-sea cold weep bacterium Erythrobacter flavus 21-3 was described. However, whether this pathway worked and what function roles it played in the cold seep were unknown. In this study, E. flavus 21-3 was verified to produce zero-valent sulfur in the cold seep using genes soxB and tsdA as our preview report described. Based on proteomic data, stoichiometric methods and microscopic observation, this ZVS formation pathway benefited E. flavus 21-3 in the deep-sea cold seep. Notably, 30% metagenomes contained these two genes in the shallow sediments, which present the most abundant sulfur genes and active sulfur cycle in the cold seep sediments. It suggested that this sulfur formation pathway exist across many bacteria in the cold seep. This strongly indicates that this novel pathway might be frequently used by microbes and plays an important role in the biogeochemical sulfur cycle in cold seep.
Project description:Dissimilatory sulfate reduction (DSR) mediated by sulfate-reducing microorganisms (SRMs) plays a pivotal role in global sulfur, carbon, oxygen, and iron cycles since ~3.5 billion years ago. The canonical DSR pathway is believed to be sulfate reduction to sulfide. Herein, we report a new DSR pathway in phylogenetically diverse SRMs through which zero-valent sulfur (ZVS) is directly generated. We identified that approximately 8.9% of sulfate reduction was directed toward ZVS with S8 as a predominant product, and the ratio of sulfate-to-ZVS could be changed with SRMs’ growth conditions, particularly the medium salinity. Further coculturing experiments and metadata analyses revealed that DSR-derived ZVS supported the growth of various ZVS-metabolizing microorganisms, highlighting this new pathway as an essential component of the sulfur biogeochemical cycle
2023-04-28 | PXD040825 | Pride
Project description:Nanoscale zero-valent iron changes microbial co-occurrence pattern in pentachlorophenol-contaminated soil
| PRJNA846560 | ENA
Project description:Dechlorination of 2,4- dichlorophenol using acclimated bacteria
