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Tao H.-C.,Peking University | Li P.-S.,Peking University | Liu Q.-S.,Key Laboratory of Chemical Genomics | Su J.,Peking University | And 2 more authors.
Journal of Chemical Technology and Biotechnology | Year: 2015

BACKGROUND: The use of cell-surface display technology to express recombinant proteins on a microbial cell surface can enhance metal adsorption to microbial cells. The transcription factor CadR of Pseudomonas putida shows highly selective affinity with Cd2+. RESULTS: CadR was genetically engineered by truncating 47N-terminal amino acids and 21 C-terminal amino acids in order to maximize its expression efficiency while maintaining its metal-binding domain. The redesigned CadR (named T68CadR) was then displayed with Saccharomyces cerevisiae a-agglutinin cell-surface display system. This engineering approach enhanced the H+/OH- buffering capacity and the Cd2+ adsorption capacity of yeast cells. The surface-engineered cells also performed well at mesophilic and higher temperatures (30-50°C) under neutral or alkalescent conditions. With an initial concentration of 1.0mgL-1, the Cd2+ removal efficiency remained 85% when the concentration of Na+ changed from 0 to 400mmolL-1 (pH 7.8). The surface-engineered cells also showed highly selective adsorption to Cd2+ in the presence of Zn2+ and Pb2+. CONCLUSIONS: T68CadR displayed yeast cells constructed in this study provide an option to selectively remove Cd in water. It also might be promising as a tool to determine CadR's Cd-binding mechanism and to improve its selectivity and affinity to Cd2+. © 2015 Society of Chemical Industry. Source

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