Application of Freeze-Dried Powders of Genetically Engineered Microbial Strains as Adsorbents for Rare Earth Metal Ions

作者：Moriwaki Hiroshi^*; Masuda Reiko; Yamazaki Yuki; Horiuchi Kaoru; Miyashita Mari; Kasahara Jun; Tanaka Tatsuhito; Yamamoto Hiroki

来源：ACS Applied Materials & Interfaces, 2016, 8(40): 26524-26531.

DOI：10.1021/acsami.6b08369

• rare earth metal ions
• Bacillus subtilis 168
• teichoic acid
• genetically engineered strains
• adsorbent

The adsorption behaviors of the rare earth metal ions onto freeze-dried powders of genetically engineered microbial strains were compared. Cell powders obtained from four kinds of strains, Bacillus subtilis 168 wild type (WT), lipoteichoic acid defective (Delta LTA), wall teichoic acid-defective (Delta WTA), and cell wall hydrolases-defective (EFKYOJLp) strains, were used as an adsorbent of the rare earth metal ions at pH 3. The adsorption ability of the rare earth metal ions was in the order of EFKYOJLp > WT > Delta LTA > Delta WTA. The order was the same as the order of the phosphorus quantity of the strains. This result indicates that the main adsorption sites for the ions are the phosphate groups and the teichoic acids, LTA and WTA, that contribute to the adsorption of the rare earth metal ions onto the cell walls. The contribution of WTA was clearly greater than that of LTA. Each microbial powder was added to a solution containing 16 kinds of rare earth metal ions, and the removals (%) of each rare earth metal ion were obtained. The scandium ion showed the highest removal (%), while that of the lanthanum ion was the lowest for all the microbial powders. Differences in the distribution coefficients between the kinds of lanthanide ions by the EFKYOJLp and Delta WTA powders were greater than those of the other strains. Therefore, the EFKYOJLp and LS, Delta WTA powders could be applicable for the selective extraction of the lanthanide ions. The Delta LTA powder coagulated by mixing with a rare earth metal ion, although no sedimentation of the WT or Delta WTA powder with a rare earth metal ion was observed under the same conditions. The EFKYOJLp powder was also coagulated, but its flocculating activity was lower than that of Delta LTA. The Delta LTA and EFKYOJLp powders have a long shape compared to those of the WT or Delta WTA strain. The shapes of the cells will play an important role in the sedimentation of the microbial powders with rare earth metal ions. As the results, three kinds of the genetically engineered microbial powders revealed unique adsorption behaviors of the rare earth metal ions.

• 出版日期2016-10-12