Biology Reference
In-Depth Information
13
CHAPTER
Synthetic Microbial
Consortia and their
Applications
Robert P. Smith, Yu Tanouchi and Lingchong You
Duke University, Durham, NC, USA
INTRODUCTION
A major goal of synthetic biology is to predictably engineer novel behaviors in cells. To
date, most efforts have been focused on engineering single populations of
Escherichia coli
,
yeast, and mammalian cells. Behaviors engineered in single populations of cells include,
but are not limited to, switches,
1
3
oscillators,
4
8
logic gates (e.g.
9
) and transcriptional
cascades (e.g.
10
).
243
It has become increasingly recognized that programming interactions between multiple
populations represents a new frontier in synthetic biology, in terms of technical challenge
and the potential implications of the resulting systems. Such multipopulation systems,
often termed consortia, have some potential advantages over systems consisting of one
population. First, a well-established consortium, such as a biofilm, is likely to be more
resistant to invasion by other microbial species.
11
Second, a properly defined mixed
population can survive transient nutrient deprivation better when different subpopulations
share essential metabolites.
12
Third, by implementing cooperating circuits in two
populations, a task that has a large metabolic burden can be shared, thus dividing the
labor between populations.
13
As such, unique behaviors can be realized in a consortium
that would be difficult to engineer in a single population. Finally, the study of synthetic
consortia may lead to novel insights into ecological and evolutionary relationships that are
difficult to study in a natural setting.
14
In this chapter, we review recent examples of synthetic microbial consortia. We describe
the unique gene circuits that allow engineered consortia to either cooperate to
perform a task or to compete against one another. Furthermore, we discuss how the spatial
structure of a consortium can lead to a novel behavior. We touch upon recent examples of
how such consortia may have relevance in industrial applications and in medicine. Finally
we outline current and future challenges in engineering consortia.
COMMUNICATION IN SYNTHETIC MULTICELLULAR SYSTEMS
A critical requirement for engineering microbial consortia is programmed communication
between populations. Communication can be implemented using small diffusible
