Microbial Biosensors: Engineered Microorganisms as the Sensing Machinery

Abstract

Whole-cell biosensors are a good alternative to enzyme-based biosensors since they offer the benefits of low cost and improved stability. In recent years, live cells have been employed as biosensors for a wide range of targets. In this review, we will focus on the use of microorganisms that are genetically modified with the desirable outputs in order to improve the biosensor performance. Different methodologies based on genetic/protein engineering and synthetic biology to construct microorganisms with the required signal outputs, sensitivity, and selectivity will be discussed.

Functional characterization of a StyS sensor kinase reveals distinct domains associated with intracellular and extracellular sensing of styrene inP. putidaCA-3

“…Traditional biosensor design has in the past largely focused on the integration of a reporter gene within the regulatory network, or "swapping" of sensor kinase domains to expand signal ranges. 32,34 However, future iterations of these strategies could benefit considerably by investigating potential transport protein associations and the impacts of their co-expression in the optimization of such systems.…”

“…Furthermore, issues of sensitivity persist, as most cannot detect inducers below µM range 41 , and signal strength and/or detection can be difficult to achieve in online systems. 32,34 In recent years the wealth of bioinformatics-based data emerging from genome studies has enabled researchers to take a fresh look at the evolution of TCSs, revealing modular protein designs displaying a limited range of structural arrangements. 7,18 Such developments have enabled researchers to refocus recombinant approaches to exploit these features in design strategies for the optimization of TCS applications.…”

Biosensors in Antimicrobial Drug Discovery: Since Biology until Screening Platforms

“…Whole cell biosensor are a choice for avoid the purification costs, in addition these sensors are easier to handle and are more stable in environments and can increase their sensitivity by the use of reporter genes [79]. Between them luciferase, which produces a light emitting reaction, is as commonly used enzyme for whole-cell biosensors, that can be employed for detect bacterial contamination.…”

FRET Imaging in Three-dimensional Hydrogels

“…They are insensitive to excitation source fluctuations and other intracellular environment factors (e.g., pH, ions) so long as both fluorophores are similarly responsive. In addition, their response is not subject to transcriptional delay, unlike fluorescent and bioluminescent promoter-reporter constructs 26,27 . Ratiometric FRET probes are easily and frequently employed in conventional widefield epifluorescence microscope systems.…”