尖孢镰刀菌(Fusarium oxysporum)诱导矿化回收稀土离子La(Ⅲ)

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

摘要:

[目的] 从罗源湾红树林浅滩土壤中筛选出产脲酶真菌，研究其对镧La（Ⅲ）的最大耐受浓度，利用其吸附和产脲酶作用诱导矿化回收稀土离子La（Ⅲ），以期为稀土离子La（Ⅲ）的资源回收提供菌种资源和应用技术指导。[方法] 从罗源湾红树林浅滩土壤中分离、筛选、纯化出可产脲酶及耐La（Ⅲ）真菌，通过ITS rDNA基因序列分析对其进行鉴定；同时，利用XRD、SEM-Mapping及FT-IR分析探讨菌株回收La（Ⅲ）的机理。[结果] 经分离、纯化得到一株可产脲酶及耐受高浓度La（Ⅲ）的真菌FZU-07，鉴定为尖孢镰刀菌（Fusarium oxysporum），其具有较强诱导矿化回收La（Ⅲ）的能力，对La（Ⅲ）的最大耐受浓度为400 mg/L。菌株FZU-07单独对La（Ⅲ）吸附回收效率为46.19%；在诱导矿化条件下回收效率可提高到99.16%。FT-IR和SEM-Mapping分析表明，尖孢镰刀菌吸附La（Ⅲ）与菌丝体表面的氨基、羟基、羰基和磷酸基团相关；XRD和SEM-Mapping结果表明诱导矿化是通过该菌的产脲酶特性，使尿素分解产生碳酸，并与钙离子结合生成球霰石晶型的碳酸钙，La（Ⅲ）被捕获在球霰石晶格中，形成La（Ⅲ）和碳酸钙的混合固相，以共沉淀的形式被回收。[结论] 菌株FZU-07，是一株具有产脲酶特性的尖孢镰刀菌（Fusarium oxysporum），且具有较强的诱导矿化回收La（Ⅲ）能力。表明微生物诱导碳酸钙沉淀是一种可行且生态友好的回收稀土离子的方法。

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.