Cooperation and coexistence in a synthetic microbial community
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Authors
Kelly, Erin E.
Issue Date
2017-05
Type
Electronic thesis
Thesis
Thesis
Language
ENG
Keywords
Chemical engineering
Alternative Title
Abstract
In this work, we develop strategies to engineer cooperation and coexistence between two industrial hosts: Gram-positive Escherichia coli and Gram-negative Bacillus megaterium. We describe the development of a minimal medium that is capable of growing both B. megaterium and E. coli separately and together. Further, we employ this medium to facilitate signal-dependent growth in an engineered cooperation system between our hosts. We demonstrate that B. megaterium is capable of controlling the growth of two E. coli strains in co-culture via a communication signal. Our signal-dependent cooperation system represents a novel approach to engineering stability between hosts. In addition, we describe the first reported case of obligate mutualism through spontaneous cross-feeding of essential metabolites between a Gram-positive and Gram-negative industrial host. Finally, we characterize partnerships based on cell enumeration rather than OD600 measurements and we discover a wide range of cross-feeding behavior where pairs can affect positive, neutral, and negative effects on their partner. We further demonstrate maintenance of both species in 3 pairs during continuous culture over 6 days. This spontaneous cross-feeding between hosts that do encounter each other in their natural environment is the first step toward intelligent design of metabolically cooperative synthetic communities.
Description
May 2017
School of Engineering
School of Engineering
Full Citation
Publisher
Rensselaer Polytechnic Institute, Troy, NY