Assimilative Manganese Oxidation as a Tolerance Strategy in Staphylococcus ureilyticus GOM10 Isolated from Deep-Sea Sediments: Implications for Biomineralization

Manganese (Mn) plays an important role in marine biogeochemical cycling; however, the mechanisms of microbial Mn oxidation in deep-sea environments remain poorly understood. This study investigated the Mn tolerance and precipitation capabilities of a novel bacterial isolate, Staphylococcus ureilyticus GOM10, isolated from deep-sea water in the Gulf of Mexico. Using a multidisciplinary approach combining microbiological, microscopic, spectroscopic, genomic, and geochemical modeling techniques, we elucidated the genetic pathways underlying Mn oxidation in GOM10. Scanning electron microscopy and energy-dispersive X-ray spectroscopy confirmed the presence of Mn-bearing precipitates associated with the bacterial cells. The strain demonstrated tolerance to Mn(II) concentrations up to 150 mM and could oxidize Mn(II) at a rate of 5.2–29.2 nM h−1. Genomic analysis revealed genes related to Mn transport and oxidation, including superoxide dismutase (SOD), peroxidases, and Mn-dependent regulators, suggesting that the Mn oxidation mechanism involves the generation of reactive oxygen species (ROS). The proposed oxidation pathway couples Mn(II) oxidation with cellular protection against oxidative stress. Our findings highlight the importance of investigating alternative pathways, such as ROS-mediated oxidation, for a more comprehensive understanding of Mn biomineralization in deep-sea environments. This study provides insights into microbial adaptations in deep-sea environments and the potential role of heterotrophic bacteria in Mn cycling.