Bacterial Manganese(II) Oxidation back to Research
Manganese(II)-oxidizing bacteria accelerate the rate of Mn biomineralization several orders of magnitude faster than abiotic processes. This biogeochemical process has gained much attention in recent years as Mn(III,IV) oxide minerals are abundant in terrestrial and marine environments. These Mn oxide minerals impact a variety of biological processes, including photosynthesis, carbon fixation, and scavenging of reactive oxygen species (ROS). Next to oxygen, Mn oxides are some of the strongest naturally occurring oxidizing agents in the environment. They participate in numerous redox and sorption reactions, thereby controlling the distributions of many other trace and contaminant elements as well as serving as a terminal electron acceptor for bacterial respiration. Dr. Tebo’s research spans the disciplines of microbiology, molecular biology, genomics, bioinorganic chemistry, mineralogy, and environmental aqueous geochemistry to investigate the molecular mechanisms of manganese oxidation by bacteria and the mechanisms by which the resulting oxide solids impact the chemistry of heavy metals and organic contaminants in soils and natural waters. We have demonstrated that Mn(II) oxidation in diverse bacteria is mediated by a novel multicopper oxidase-like protein. Recent studies using synchrotron-based X-ray absorption spectroscopy have shown that biogenic Mn oxides are nanoparticulate, cryptocrystalline materials and are representative of the most highly reactive and important Mn oxide phases in the environment. Research projects in the lab address questions such as why bacteria oxidize Mn(II), can Mn(II)-oxidizing bacteria be used for heavy metal removal and bioremediation, what are the properties of the biogenic Mn oxide minerals, how do bacteria influence the biogeochemical cycling of Mn in the environment and how are they influenced by environmental factors? Specific environments studied include the oxic/anoxic transition zones that occur in anoxic water bodies (e.g., the Black Sea), at hydrothermal vents, and on rock and mineral surfaces.