新型锰氧化菌株 Pseudoxanthomonas mexicana S5-3_-5X 的分离及锰氧化机理研究

Mn^II-oxidizing microorganisms catalyze the formation of Mn oxides from Mn^II, which can enhance the degradation of trace organic pollutants in water treatment systems（such as manganese sand filters and wetlands）and the anaerobic oxidation of methane from sediment, thus being widely studied. The isolation of Mn^II-oxidizing bacteria with different ecological niches from the environment is an important basis for the bioaugmentation of the Mn^II oxidization process in the environment. According to the potential preference of Mn^II-oxidizing strains for low concentration of nutrients, a common Mn^II-oxidizing bacteria medium was series diluted to prepare five culture media with lower concentrations of nutrients. Compared with the original medium, Mn^II-oxidizing strains of additional 6 genera were isolated from the four diluted culture media, improving the isolation efficiency of Mn^II-oxidizing strains. An newly isolated Pseudoxanthomonas Mn^II-oxidizing strain（Pseudoxanthomonas mexicana S5-3-5X）was reported for the first time. The strain could grow under mild environmental conditions（pH 6.0~7.8；low nutrient concentration（e.g., PYG culture media diluted 5 to 625 times）；Mn^II concentrations was in the range of 50 μmol·L^-1 to 1.6 mmol·L^-1）. The strain produced Mn^II-oxidizing activity by producing both extracellular superoxide radical and Mn^II-oxidizing protein. Its genome encoded three Mn^II-oxidizing protein homologs of a Mn^II-oxidizing type stain Pseudomonas putida GB-1 and has metabolic pathways for degrading organic pollutants. Therefore, the strain has particular engineering application potential.