Portable Microalgal Biosensor for Herbicide Monitoring

Abstract

The need for in-situ and real-time tools to monitor the fate of pesticides in extensive areas is of great concern to preserve the environment in countries where agroindustry represents an essential part of its economy. In this work, we present the construction of a portable system based on the reversible photosynthesis inhibition produced by herbicides on microalgae, using atrazine as a model compound. The decrease in oxygen production due to the photosynthesis inhibition is electrochemically detected using an automated flow system. The system presented here involves the immobilization of microalgae in a polyelectrolyte-surfactant-carbon nanotube self-assembled material cast on a screen-printed graphite electrode; these components contribute to the stability and sensitivity of the whole device. The system presents a limit of detection of 0.11 μM, showing an excellent performance in river samples. The sensor maintains its integrity after five months immersed in a freshwater algae medium at room temperature. These features are key to install this system along the course of a river at a low cost, allowing early detection of polluted areas and long term environmental studies.

Extremozyme-Based Biosensors for Environmental Pollution Monitoring: Recent Developments

“…This is probably due to their relatively easy preparation by established protocols and lack of commercially available extremophilic preparations. The effort to develop analytical devices with enhanced stability, while minimizing the costs and environmental impact, is illustrated by, e.g., (i) a mediatorless electrochemical biosensor based on microalgae that retained 93% of initial activity after 5 months of storage at room temperature and detected atrazine in spiked river water [ 232 ]; (ii) an optical, environmentally friendly sensor obtained by immobilizing Chlamydomonas reinhardtii on a paper substrate for the detection of nanoformulated atrazine (herbicide), with a stability of 3 weeks at room temperature [ 233 ]; or (iii) a bioassay based on Chlorella mirabilis and chlorophyll fluorescence, integrated in an automated marine buoy that was operated by telemetry and used to detect herbicides in coastal waters [ 234 ].…”

Whole-Cell Microbial Bioreporter for Soil Contaminants Detection

“…The alginate beads were deployed on the surface of the soil to detect volatile contaminants like toluene, and the bioluminescence was measured via a fiber-optic probe. Bioelectrochemical systems can also be employed in organic contaminant detection, in which bioreporters were immobilized on electrodes ( Boron et al, 2020 ). Recently, Boron et al (2020) have developed a herbicide bioreporter based on the suppression of photosynthesis by atrazine.…”

“…Bioelectrochemical systems can also be employed in organic contaminant detection, in which bioreporters were immobilized on electrodes ( Boron et al, 2020 ). Recently, Boron et al (2020) have developed a herbicide bioreporter based on the suppression of photosynthesis by atrazine. In this system, microalgae Monoraphidium contortum are fixed on the screen-printed graphite electrode.…”

“…In this system, microalgae Monoraphidium contortum are fixed on the screen-printed graphite electrode. The decreased oxygen production can be measured by electrochemical methods ( Boron et al, 2020 ).…”

“…For example, the visual signals from bioreporters in microfluidic devices can be captured by the miniaturized photomultiplier detectors ( Roggo and van der Meer, 2017 ). The electrochemical bioreporter can be easily integrated into field-applicable electric devices ( Ben-Yoav et al, 2009 ; Boron et al, 2020 ). The integration of emerging disciplines such as artificial intelligence, big data, smart mobile devices, and drones will be necessary to close the gap between research and field application and realize long-term online monitoring of soil contamination.…”