Development of bacteria-based bioassays for arsenic detection in natural waters

Abstract

Arsenic contamination of natural waters is a worldwide concern, as the drinking water supplies for large populations can have high concentrations of arsenic. Traditional techniques to detect arsenic in natural water samples can be costly and time-consuming; therefore, robust and inexpensive methods to detect arsenic in water are highly desirable. Additionally, methods for detecting arsenic in the field have been greatly sought after. This article focuses on the use of bacteria-based assays as an emerging method that is both robust and inexpensive for the detection of arsenic in groundwater both in the field and in the laboratory. The arsenic detection elements in bacteria-based bioassays are biosensor-reporter strains; genetically modified strains of, e.g., Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Rhodopseudomonas palustris. In response to the presence of arsenic, such bacteria produce a reporter protein, the amount or activity of which is measured in the bioassay. Some of these bacterial biosensor-reporters have been successfully utilized for comparative in-field analyses through the use of simple solution-based assays, but future methods may concentrate on miniaturization using fiberoptics or microfluidics platforms. Additionally, there are other potential emerging bioassays for the detection of arsenic in natural waters including nematodes and clams.

Role of Aspergillus niger acrA in Arsenic Resistance and Its Use as the Basis for an Arsenic Biosensor

“…The field-based methods in current use are cost-effective but produce toxic by-products and use dangerous reagents like mercury (5,21) and hydrochloric acid, which are not ideal to transport and handle in the field (5). Most whole-cell biosensors reported to date are based on bacterial systems (7,22,29). The ⌬acrA::P acrA -GFP biosensor strain is the first fungal biosensor for arsenic detection.…”

“…The majority of arsenicresponsive biosensor bacterial strains use reporter constructs based on the transcriptional repressor arsR (22,64). Cross-reactions with antimony and other metalloids have been described using this gene (50).…”

“…These tests require the use of hazardous chemicals and can generate toxic by-products. Biosensors and bioreporters are beginning to emerge as safe, alternate methods to detect environmental pollutants such as arsenic (22,29,50). Although several arsenic biosensors have been reported, these traditionally rely on bacterial reporter systems (7), which have a relatively narrow tolerance to variation in culture systems, transportation, and storage.…”

Isolation, identification and characterization of arsenic transforming exogenous endophytic Citrobacter sp. RPT from roots of Pteris vittata

“…Microorganisms are primarily used in the bioremediation to degrade or detoxify the As into harmless and less toxic forms. Several microbial processes involve the removal of As in soil and water, including oxidation, reduction, adsorption and microbemediated electron transfer (Diesel et al 2009;Guo et al 2015). Generally As is toxic to microorganisms; however, several microorganisms gain the energy for rapid growth by metabolizing the As Stolz 2003, 2005).…”

Miniaturized bacterial biosensor system for arsenic detection holds great promise for making integrated measurement device

“…The reason to focus on a bioreporter system for arsenic is that contamination of drinking water resources with arsenic is a world-wide problem occurring in both industrialized and developing countries. 4 Moreover, several geographical regions that currently suffer most from extensive arsenic contamination, such as Vietnam, Bangladesh, India and Cambodia, 5 are also the areas without the typical infrastructure needed to reliably measure arsenic down to μg per L concentrations to comply with typical drinking water standards. Given over time can probably not be completely avoided.…”