一株台湾红酵母(Rhodotorula taiwanensis)的鉴定及其除Mn(Ⅱ)性能研究

Identification of a Rhodotorula taiwanensis strain capable of removing Mn(Ⅱ)

摘要:

【目的】探究一株红酵母对Mn(Ⅱ)的去除效率及其作用机制。【方法】从酸性矿山废水中分离出一株耐酸酵母菌，通过形态和26S rRNA基因测序对菌种进行鉴定，研究不同pH和Mn(Ⅱ)浓度对该菌除Mn(Ⅱ)效果的影响。采用扫描电镜、X射线衍射分析和X射线光电子能谱仪进行产物表征。【结果】分离得到的酵母菌经鉴定为台湾红酵母(Rhodotorula taiwanensis)，其在pH 2.0、2 000 mg/L Mn(Ⅱ)条件下仍能生长较好。在初始pH 6.0、Mn(Ⅱ) 300 mg/L条件下培养144 h后,对Mn(Ⅱ)的去除率能达到98.52%；然而较高浓度的Mn(Ⅱ) (≥500 mg/L)会对细胞产生毒性，从而降低去除效果。R. taiwanensis MF4在去除Mn(Ⅱ)的过程中可以将Mn(Ⅱ)氧化成锰氧化物(主要为无定型的MnO₂、Mn₂O₃、MnO)，形成层状物质在细胞表面积累，而且能产生碱度，提升环境pH值，最高可达8.4 [初始pH 7.0，Mn(II) 100 mg/L，144 h]。【结论】R. taiwanensis MF4具有耐受低pH和高浓度Mn(II)、有效去除Mn(II)以及产碱的作用，研究结果对酸性矿山废水修复与治理的末端工艺设计具有参考价值。

关键词:锰离子;红酵母;除锰机制;产碱;酸性矿山废水

Abstract:

[Objective] To investigate the removal efficiency and mechanism by a strain of Rhodotorula. [Methods] The strain was identified based on the morphological characteristics and the phylogenetic tree based on 26S rRNA gene sequences. Then, the removal effect of the strain on Mn(II) was studied at different initial pH and Mn(II) concentrations. Finally, the products were characterized by scanning electron microscopy, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. [Results] The isolate was identified as Rhodotorula taiwanensis, which could grow well at pH 2.0 and 2 000 mg/L Mn(II). The removal rate of Mn(Ⅱ) by the strain reached 98.52% at the initial pH 6.0 and Mn(II) concentration of 300 mg/L after 144 h, while higher concentrations (≥500 mg/L) of Mn(II) caused toxicity to the cells and weakened the removal effect. The strain could oxidize Mn(II) to manganese oxides (mainly amorphous MnO₂, Mn₂O₃, and MnO), which produced layered minerals accumulated on the cell surface. In addition, the process of removing Mn(II) by the strain increased the pH of the medium (initial pH 7.0, Mn(II) concentration of 100 mg/L) up to 8.4 after 144 h. [Conclusion] R. taiwanensis MF4 isolated in this study can tolerate low pH and high concentrations of Mn(II), remove Mn(II), and increase medium pH. The findings have a reference value for the end process design in the remediation and treatment of acid mine drainage.

Key words:manganese ion;Rhodotorula taiwanensis;manganese removal mechanism;alkali production;acid mine drainage