US EPA

1519072 

Journal Article 

Expression of arsenic regulatory protein in Escherichia coli for selective accumulation of methylated arsenic species 

Yang, T; Liu, J-W; Gu, C; Chen, M-L; Wang, J-H 

2013 

1 

ACS Applied Materials & Interfaces
ISSN: 1944-8244
EISSN: 1944-8252 

5 

7 

2767-2772 

English 

23484908 

10.1021/am400578y 

WOS:000317549100063 

ArsR is a metalloregulatory protein with high selectivity and affinity toward arsenic. We hereby report the expression of ArsR in Escherichia coli by cell engineering, which significantly enhances the adsorption/accumulation capacity of methylated arsenic species. The ArsR-expressed E. coli cells (denoted as E. coli-ArsR ) give rise to 5.6-fold and 3.4-fold improvements on the adsorption/accumulation capacity for monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), with respect to native E. coli cells. The uptake of MMA and DMA by the E. coli-ArsR is a fast process fitting Langmuir adsorption model. It is interesting to note that the accumulation of methylated arsenic is virtually not affected by the presence of competing heavy-metal species, at least 10 times of Cd(II) and Pb(II) are tolerated for the adsorption of 1 mg L(-1) methylated arsenic. In addition, an ionic strength of up to 2 g L(-1) Na(+) poses no obvious effect on the sorption of 1 mg L(-1) MMA and DMA. Furthermore, the accumulation of MMA and DMA is less sensitive to the variation of pH value, with respect to the blank control cells. Consequently, 82.4% of MMA and 96.3% of DMA at a concentration of 50 μg L(-1) could be readily removed from aqueous medium by 12 g L(-1) of E. coli-ArsR . This illustrates a great potential for the E. coli-ArsR for selective remediation of methylated arsenic species in waters, even in the presence of a high concentration of salts.