F.SM01.09.06 Living Sorbents for Arsenic-Contaminated Drinking Water Remediation
Arsenic contamination is a growing problem in several parts of the world today. According to the FDA guidelines, Arsenic levels in Food and Dietary supplements must be regulated less than 10 ppb. But, arsenic levels in groundwater found in Bangladesh, Mexico, Argentina, Western USA, etc are rising to an alarming level. As arsenic poisoning can lead to adverse conditions to cardiovascular health, immune, and nervous system, to resolve this crisis, the presenter of this talk Yidan Bi(Brown University) looks for clues from natural detoxification mechanisms.
The toxicity of As(III) originates from its high affinity to the cysteine residues in proteins. So, the group engineered a benign strain of E. coli to overexpress specific fusion proteins which can impart an improved arsenic scavenging competency. This system is advantageous as it can easily sequester arsenic As(III) ions and bioaccumulate the arsenic. And the arsenic sorption capacity can be hastened to immobilize milligrams of arsenic in a few hours.
The Arsenic removal performance of the biosorbent cells was found to be much better compared to bayoxide in synthetic water as well as various other water matrices (such as altered pH and different salt concentrations). Moreover, the team was able to remove arsenic from water-matrices such as juice and wine. Lastly, to reduce secondary contamination, the bacteria from water is removed using magnetic-assisted labeling. Magnetic nanoparticles are used to label the engineered E. coli bio-sorbent cells which are then easily removed from the system using external magnets. Other solutions like pre-treatment or extensive removal of competing ions along with arsenic could increase the operation cost and unnecessarily eliminate other benign species from water. Comparatively, this method could be cost-friendly and accessible to rural areas that do not have access to fresh potable water and arsenic contaminant removal technology.