Fusarium oxysporum induces mineralization recovery rare earth ions Lanthanum (Ⅲ)

Abstract:

[Objective] The urease-producing fungus was screened from the sediment of mangrove in Luoyuan Bay. Study the best tolerance concentration of strains to La(Ⅲ), and use the urease-producing properties of the strains to induce mineralization and recovery of La(Ⅲ). It was expected to provide strain resources and application technology references for resource recovery of rare earth ions La(Ⅲ). [Methods] The urease-producing and La-resistant strains were isolated, screened and purified from the mangrove sediment of Luoyuan Bay, and identification was made through ITS rDNA gene sequence analysis. Meanwhile, the mechanisms of recover La(Ⅲ) were discussed by XRD, SEM-Mapping and FT-IR analysis. [Results] A urease-producing and high-concentration La(Ⅲ)-tolerant fungus was obtained by isolation and purification, which was identified as Fusarium oxysporum-FZU-07. Strain FZU-07 has a strong ability to recovery of La(Ⅲ), and the maximum La(Ⅲ) tolerance concentration is 400 mg/L. The recovery efficiency of strain FZU-07 for La(Ⅲ) adsorption was 46.19%, and the recovery efficiency could be increased to 99.16% under the condition of induced mineralization. FT-IR and SEM-Mapping analysis showed that the functional group of amido, hydroxyl, carbonyl and phosphate on the cell surface played a principal role to adsorption of La(Ⅲ). XRD and SEM-Mapping analysis showed that induction of mineralization is through the urease-producing characteristics of the strain, which decomposes urea to produce carbonic acid, and combines with calcium ions to form vaterite crystal (calcium carbonate). La(Ⅲ) was removed via incorporation into the lattice of calcium carbonate particles and formed mixed crystal. [Conclusion] The strain FZU-07 was identified as Fusarium oxysporum, with urease-producing properties and strong ability to induce mineralization and recovery of La(Ⅲ). The results indicate that the microbial induced calcium carbonate precipitation method is a feasible and eco-friendly technology for the recovering rare earth ions.