Expression of synthetic Phytochelatin EC20 in E. Coli increases its biosorption capacity and cadmium resistance

Authors

  • Cleide Barbieri de Souza Universidade de São Paulo
  • Elisabete José Vicente Universidade de São Paulo

DOI:

https://doi.org/10.14393/BJ-v36n2a2020-42463

Keywords:

Escherichia coli, Phytochelatin, Biosorption, Bioremediation, Cadmium.

Abstract

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.

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Published

2020-02-11

How to Cite

SOUZA, C.B. de and VICENTE, E.J., 2020. Expression of synthetic Phytochelatin EC20 in E. Coli increases its biosorption capacity and cadmium resistance. Bioscience Journal [online], vol. 36, no. 2, pp. 619–627. [Accessed8 December 2022]. DOI 10.14393/BJ-v36n2a2020-42463. Available from: https://seer.ufu.br/index.php/biosciencejournal/article/view/42463.

Issue

Section

Biological Sciences