Enhanced arsenic accumulation in engineered bacterial cells expressing ArsR

Area of Science:

• Environmental Microbiology
• Biotechnology
• Environmental Science

Background:

• Arsenic contamination in water poses significant health risks.
• The metalloregulatory protein ArsR exhibits high affinity and selectivity for arsenite.
• Previous attempts to enhance arsenic bioaccumulation using ArsR led to reduced cell growth.

Purpose of the Study:

• To improve arsenic bioaccumulation by overexpressing ArsR in Escherichia coli.
• To overcome growth inhibition associated with ArsR overexpression.
• To develop a biotechnological solution for arsenic removal from contaminated water.

Main Methods:

• Overexpression of the metalloregulatory protein ArsR in Escherichia coli.
• Fusion of ArsR with an elastin-like polypeptide (ELP153AR) to improve cell viability.
• Assessing arsenate and arsenite bioaccumulation in engineered cells.
• Testing the efficiency of engineered cells for arsenic removal from contaminated water.

Main Results:

• ArsR overexpression increased arsenite bioaccumulation but reduced cell growth.
• The ELP153AR fusion protein improved cell growth twofold without compromising arsenite accumulation.
• Engineered cells accumulated 5-fold higher arsenate and 60-fold higher arsenite compared to controls.
• 100% removal of 50 ppb arsenite from water was achieved, meeting U.S. EPA standards.

Conclusions:

• Fusion of ArsR with ELP enhances its utility for arsenic bioaccumulation.
• Engineered cells show high specificity for arsenic, with no significant uptake of cadmium or zinc.
• Overexpressing ArsR presents a promising, cost-effective method for arsenic remediation in water.