不同长度金属结合肽对大肠杆菌吸附钯性能的影响

利用微生物吸附法回收铂族金属(PGMs)有较大的应用前景，然而利用基因工程手段改造微生物胞外金属结合基团，进而提升微生物的吸附量与特异性仍是一项挑战。本研究利用微生物表面展示技术，在大肠杆菌(Escherichia coli，简写为E. coli)BL21菌株外膜上展示了不同长度的金属结合肽(EC10、EC20、EC30)，并解析了其对钯(Pd(II))的吸附行为。结果表明，在E.coli BL21表面展示不同长度金属结合肽均能增强其对Pd(II)的吸附量。其中，表面展示了EC20的菌株(简写为E. coli EC20)吸附量最高，为144.25 mg/g，是未进行表面展示菌株的1.14倍；E. coli BL21和E. coli EC20均能够从含多种金属离子的工业废水中选择性吸附Pd(II)和Pt(IV)，两株菌对Pd(II)吸附率分别为96.2%和99.0%。以上研究表明利用表面展示技术增加微生物外膜金属结合基团是一种有效提升微生物吸附能力的手段。

Effect of Different Length Metal-Binding Peptides on the Palladium Adsorption Performance of E. coli

The recovery of platinum group metals (PGMs) by microbial adsorption has potential application prospects. However, it is still a challenge to modify the extracellular metal-binding groups of microorganisms so as to improve the adsorption capacity and specificity by genetic engineering. In this study, we displayed different lengths metal-binding peptides (EC10, EC20, EC30) on the outer membrane of E. coli BL21 by microbial surface display technology, and further analyzed their adsorption behavior to Pd(II). The results show that the display of metal-binding peptides of different lengths on the surface of E. coli BL21 all improved the adsorption capacityon Pd (II). Among them, the strain with EC20 displayed on the surface (E. coli EC20) has the highest adsorption capacity of 144.25 mg/g, which is 1.14 times that of the strain without surface display; Both E. coli BL21 and E. coli EC20 can selectively adsorb Pd(II) and Pt(IV) from industrial wastewater containing various metals, and the recovery rates for Pd(II) are 96.2% and 99.0%, respectively. This study shows that using surface display technology to increase the metal binding groups of the outer membrane of microorganisms is an effective means to improve the adsorption capacity of microorganisms.