A Framework for the Systematic Selection of Biosensor Chassis for Environmental Synthetic Biology

Abstract

Microbial biosensors sense and report exposures to stimuli, thereby facilitating our understanding of environmental processes. Successful design and deployment of biosensors hinge on the persistence of the microbial host of the genetic circuit, termed the chassis. However, model chassis organisms may persist poorly in environmental conditions. In contrast, non-model organisms persist better in environmental conditions but are limited by other challenges, such as genetic intractability and part unavailability. Here we identify ecological, metabolic, and genetic constraints for chassis development and propose a conceptual framework for the systematic selection of environmental biosensor chassis. We identify key challenges with using current model chassis and delineate major points of conflict in choosing the most suitable organisms as chassis for environmental biosensing. This framework provides a way forward in the selection of biosensor chassis for environmental synthetic biology.

Keywords: biosensor; chassis; environmental; marine; soil; synthetic biology.

Figure 1

The journey from native organism to biosensor chassis. We recommend isolating organisms native to the ecosystems and environments of interest. After eliminating agricultural pathogens, a list of safe organisms will remain that can be narrowed down further based on our framework. This process results in a list of candidate chassis that, after sufficient biocontainment, can be tested in lab simulations of natural environments and evaluated for performance and persistence.

Figure 2

Prioritizing chassis constraints. It is challenging to resolve all our constraints in the selection of a chassis organism. In such cases, prioritizing some constraints over others can be a useful way forward. We recommend the above priority axis as a guide to negotiate the various constraints in the choice of a chassis organism.