Field Testing of Arsenic in Groundwater Samples of Bangladesh Using a Test Kit Based on Lyophilized Bioreporter Bacteria

Abstract

A test kit based on living, lyophilized bacterial bioreporters emitting bioluminescence as a response to arsenite and arsenate was applied during a field campaign in six villages across Bangladesh. Bioreporter field measurements of arsenic in groundwater from tube wells were in satisfying agreement with the results of spectroscopic analyses of the same samples conducted in the lab. The practicability of the bioreporter test in terms of logistics and material requirements, suitability for high sample throughput, and waste disposal was much better than that of two commercial chemical test kits that were included as references. The campaigns furthermore demonstrated large local heterogeneity of arsenic in groundwater, underscoring the use of well switching as an effective remedy to avoid high arsenic exposure.

Electrochemical As(III) whole-cell based biochip sensor

“…As a result, the complete biosensing assay can be performed inside a single disposable microchip containing 16 independent electrochemical cells for the in situ monitoring of β-Gal activity produced by an Escherichia coli arsenic sensitive bioreporter within 25 min-50 min for 7.5 ppb As (III), in comparison to other arsenic sensitive bacterial bioreporters and with a high sensitivity (LOD¼0.8 ppb) (vide infra). Multiple sample analysis in series can further reduce the effective time for a single analysis to 10 min or less (Siegfried et al 2012). Moreover, we validated the present methodology by comparing the bioreporter assay response with atomic absorption spectroscopy (AAS) on arsenic contaminated groundwater samples from Swiss mountain areas and from Romania.…”

Escherichia coli ribose binding protein based bioreporters revisited

“…Construction of bioreporter bacteria typically starts with identifying a sensory protein that controls expression of a target gene promoter in dependence on one or more chemical inducers12345678. As an example, the ArsR protein represses its cognate promoter P ars , but when cells are exposed to arsenite (AsIII), this oxyanion will interact with ArsR causing it to lose affinity for the operator site close to P ars , thus increasing the rate of transcription from P ars 6.…”

The Chromobacterium violaceum ArsR Arsenite Repressor Exerts Tighter Control on Its Cognate Promoter Than the Escherichia coli System

“…From a historical perspective, most synthetic circuits constructed in bacteria have been implemented using components from the model organism E. coli (Church et al, 2014). This has indeed been the case for biosensors designed to detect arsenic in environmental samples with several designs having been constructed by shuffling the ars components of E. coli (Siegfried et al, 2012, 2015; Wang et al, 2015; Merulla and van der Meer, 2016). Since the World Health Organization (WHO) recommended acceptable limit for drinking water of 10 μg/L arsenic, any modification of natural arsenic sensing systems for biosensing purposes should aim increasing responsivity of the systems to concentrations close to this limit.…”

“…In this sense, developed biosensors proved to be useful tools for arsenite and arsenate detection in groundwater (Siegfried et al, 2012) and river water (Siegfried et al, 2015) as a low cost, suitable and transportable alternative to detect the metalloid to prevent or diminish arsenic exposure. Furthermore, the advent of biological circuit design approaches in the field of synthetic biology has allowed the re-wiring of basic molecular components (regulators, DNA binding sites, and operators), which can be reinserted into the host cell to give rise to sensors with enhanced performance (Stocker et al, 2003; Trang et al, 2005; Fernandez et al, 2016; Merulla and van der Meer, 2016).…”