Expression of synthetic Phytochelatin EC20 in E. Coli increases its biosorption capacity and cadmium resistance
Keywords:Escherichia coli, Phytochelatin, Biosorption, Bioremediation, Cadmium.
In this study E. coli recombinant clones that express the EC20 synthetic phytochelatin intracellularly were constructed. The increasement of Cd2+ biosorption capacity, and, also, the increasement of resistance to this toxic metal were analyzed. A gene that encodes the synthetic phytochelatin EC20 was synthesized in vitro. The EC20 synthetic gene was amplified by PCR, inserted into the DNA cloning vectors pBluescript®KS+ and pGEM®-TEasy, and also into the expression vectors pTE [pET-28(a)® derivative] and pGEX-T4-2®. The obtained recombinant plasmids were employed for genetic transformation of E. coli: pBsKS-EC20 and pGEM-EC20, they were introduced into DH10B and DH5α strains, similarly to pTE-EC20 and pGEX-EC20 that were introduced into BL21 strain. The EC20 expression was confirmed by SDS-PAGE analysis. The recombinant clones’ resistances to Cd2+ were determined by MIC analyses. The MIC for Cd2+ of DH10B/pBKS-EC20 and DH10B/pGEM-EC20 were 2.5 mM (EC20 induced), and 0.312 mM (EC20 repressed); respectively, 16 and 2 times higher than the control DH10B/pBsKS (0.156 mM). The MIC for Cd2+ of BL21/pTE-EC20 was 10.0 mM (EC20 induced) and 2.5 mM (EC20 repressed), compared with the control BL21/pTE which was only 1.25 mM. Analysis of ICP-AES showed that BL21/pGEX-EC20, after growth on the condition of EC20 expression, absorbed 37.5% of Cd2+, and even when cultured into the non-induction condition of EC20 expression, it absorbed 11.5%. These results allow the conclusion that recombinant E. coli clones expressing the synthetic phytochelatin EC20 show increased capacity for Cd2+ biosorption and enhanced resistance to this toxic ion.
How to Cite
Copyright (c) 2020 Cleide Barbieri de Souza, Elisabete José Vicente
This work is licensed under a Creative Commons Attribution 4.0 International License.