Determination of heavy metals in aqueous solutions via microbial biosensors

Biosensors are strong alternatives to conventional analytical techniques such as HPLC and spectroscopic methods for water quality and heavy metal detection. Heavy metal contaminated waters can monitor by microbial biosensors efficiently. For this purpose, newly isolated Stenotrophomonas maltophilia and Pseudomonas marincola. are used to develop a highly sensitive low-cost microbial biosensor for water quality monitoring. The objective of the study is the invention of new, highly sensitive low-cost microbial biosensors to determine heavy metals in aqueous solutions and optimise the working conditions. The study shows that the Stenotrophomonas maltophilia sensor was found in a linear range between 1x10−8 M and 6x10−8 M (0.01-0.06 µM), with the lowest detection limit 10−9 M (0.001 µM). The Pseudomonas marincola. sensor was found in a linear range between 1x10−8 M and 8x10−8 M (0.01-0.08 µM), with the lowest detection limit 10−9 M (0.001 µM). The optimum pre-concentration time and scan rate were measured for both sensors as 10 minutes and 10 mV/s, respectively. The results support that the new isolated Stenotrophomonas maltophilia and Pseudomonas marincola. have significant potential to determine the trace amount of Pb+2 in aqueous solutions. The designed low-cost biosensor does not require any mediator for electrochemical response or fixator to embed on the Screen Printed Electrode (SPE) surface. Living cells can fix on the surface under laminar flow conditions without extra effort. The designed biosensor can be prepared and detect Pb in under 30 min from the initial step to the final stage.