Biology Reference
In-Depth Information
Engineering Synthetic Ecosystems
coupled
metabolisms
intercellular
communication
biosensing
biodegradation
biosynthesis
defined spatial
structures & associations
FIGURE 17.1
Engineering ecology requires the synthesis of metabolism, communication, and spatial architecture to generate synthetic
ecosystems that can productively sense, degrade, or produce a myriad of biomolecules of industrial, medical or commercial
value.
Spatial organization importantly determines the scale of interactions that can occur between
given cells as a result of local proximity. Locality has a critical influence over metabolic
exchange and signaling in synthetic communities.
46
48
New microfluidic and microdroplet
devices have recently been developed to reproduce interactions between spatially defined
communities,
47,49,50
formation of structured biofilms,
51
and cell
cell aggregations,
52
and
will continue to play an important experimental role.
TOWARDS SYNTHETIC COMMUNITY ENGINEERING
Advances in synthetic biology are beginning to be applied to multispecies systems with
direct real-world applications. While most examples of synthetic ecosystems involve only
two or three distinct strains, they represent substantial improvement in our capability to
engineer complex microbial interactions.
28
We outline different applications of synthetic
microbial communities to highlight their potential in improving areas of biosensing,
biosynthesis, and biodegradation, where the capabilities of homogeneous populations of
genetically identical cells are insufficient (
Fig. 17.2
).
319
Biosensing
Abilities to sense diverse environmental signals and actuate appropriate responses are
necessary and key features of engineered microbial communities. For example,
autodetection of changes among networks of gut microbes in the intestine would allow for
real-time monitoring and pinpointed responses to alarming events such as infections or
toxins. Such capabilities would present a marked improvement over current monitoring
strategies, where symptoms are only recognized once an infection has fully developed and
treatment requires indiscriminant depletion of the native community using antibiotics.
These population-level behaviors are only now being demonstrated using synthetic
communication circuits with quorum sensing modules. Nonpathogenic
Escherichia coli
has
been engineered to recognize specific QS molecules diffusing from virulent strains of
Vibrio
53
or
Pseudomonas
.
54
Upon detection, pathogen-specific antimicrobial proteins or
compounds are released, resulting in 99% reduction in the pathogen load.
54
Synthetic consortia can also be designed to detect and respond to other compounds to
regulate programmed behaviors. Consortia growth rate and relative abundances of different
members can be tuned in response to the environment.
36,55
These approaches can be used to
engineer biofilms to alter its physical architecture and membership composition, to optimize
bioprocesses that rely on spatially associated communities.
56
Engineered communities can
also be used not only to microscopically sense low-level metabolites, but also to amplify
the signal for macroscopic detection. Building on an oscillatory fluorescence-generating
