Bioengineering of non-pathogenic Escherichia coli to enrich for accumulation of environmental copper

Abstract

Heavy metal sequestration from industrial wastes and agricultural soils is a long-standing challenge. This is more critical for copper since copper pollution is hazardous both for the environment and for human health. In this study, we applied an integrated approach of Darwin’s theory of natural selection with bacterial genetic engineering to generate a biological system with an application for the accumulation of Cu2+ ions. A library of recombinant non-pathogenic Escherichia coli strains was engineered to express seven potential Cu2+ binding peptides encoded by a ‘synthetic degenerate’ DNA motif and fused to Maltose Binding Protein (MBP). Most of these peptide-MBP chimeras conferred tolerance to high concentrations of copper sulphate, and in certain cases in the order of 160-fold higher than the recognised EC50 toxic levels of copper in soils. UV–Vis spectroscopic analysis indicated a molar ratio of peptide-copper complexes, while a combination of bioinformatics-based structure modelling, Cu2+ ion docking, and MD simulations of peptide-MBP chimeras corroborated the extent of Cu2+ binding among the peptides. Further, in silico analysis predicted the peptides possessed binding affinity toward a broad range of divalent metal ions. Thus, we report on an efficient, cost-effective, and environment-friendly prototype biological system that is potentially capable of copper bioaccumulation, and which could easily be adapted for the removal of other hazardous heavy metals or the bio-mining of rare metals.

Synthetic bacteria for the detection and bioremediation of heavy metals

“…Lately, a putative U-shaped Cu-binding peptide was developed by screening synthetic degenerate DNA fragments, and the peptide was then conjugated at the C-terminus of the maltose-binding protein (MBP) ( Gahlot et al, 2020 ). E. coli cells displaying the fusion of MBP and Cu-binding peptide demonstrated efficient Cu-binding and tolerance to up to 4 mM of Cu 2+ .…”

Inhibition of the BNIP3/NIX‐dependent mitophagy aggravates copper‐induced mitochondrial dysfunction in duck renal tubular epithelial cells

“…Artificial activities have resulted in elevated Cu concentrations that far exceed current environmental level quality standards, which poses a massive risk to the health of living organisms. Water and food are the main routes of Cu contamination to which organisms in the environment are exposed, causing physical and chemical damage 2 . The toxic effects of Cu include damage to target tissues, especially interference with ion and osmotic regulation and programmed death of cells 3 .…”

“…Water and food are the main routes of Cu contamination to which organisms in the environment are exposed, causing physical and chemical damage. 2 The toxic effects of Cu include damage to target tissues, especially interference with ion and osmotic regulation and programmed death of cells. 3 The effect on the kidney is one of Cu limited dose toxicity, including renal tubular injury leading to electrolyte waste and glomerular filtration dysfunction.…”

In Vitro and In Silico Analysis of the Gut Microbiome of Zebrafish for Bioremediation Approach of Zinc-Contaminated Aquatic Environments

“…3 Å [49],[50]. Beta-lactamase of both bacteria (Enterobacter cloacae and Citrobacter freundii) shows the least binding affinity, and beta-lactam antibiotics are rendered inactive by this enzyme by hydrolyzing the peptide link of the distinctive four-membered beta-lactam ring.…”