# Programmable benchtop bioreactors for scalable eco-evolutionary dynamics of the human microbiome

> **NIH NIH R01** · BOSTON UNIVERSITY (CHARLES RIVER CAMPUS) · 2022 · $867,648

## Abstract

PROJECT SUMMARY/ABSTRACT
Antibiotic-resistant microbial pathogens are a grave and urgent threat to public health. With rising rates of drug-
resistant infections and a diminishing arsenal of new antibiotic treatments, there is pressing need for
approaches to better understand, predict, and prevent the emergence of antimicrobial resistance (AMR). To
this end, experimental evolution approaches, in which microbial organisms are evolved in the laboratory in
user-defined conditions, provide a powerful paradigm to define the evolutionary paths toward AMR. This
approach has illuminated genetic pathways to evolving resistance, and can define factors that can be exploited
to steer toward drug-susceptible states and guide new clinical strategies. However, the potential of this
approach for understanding AMR evolution is fundamentally constrained by technological barriers in
conducting continuous culture and evolution experiments, which requires the following key capacities: 1) Scale
to evolve across a diversity of microbes, experimental conditions, and antibiotics; 2) Automation for frequent
perturbations and feedback over long experimental time scales; 3) Control to reproduce key features of the
mammalian gut environment, a primary site for the evolution of AMR in vivo. All existing tools fail in one or
more of these capacities. And critically, laboratory evolution studies fail to account for how interactions within
bacterial communities impact the evolutionary trajectory, dynamics, and outcomes of AMR. We propose to fill
this technological and experimental void by developing a first-in-class, benchtop technology for scalable,
automated, and controlled microbial evolution studies, and apply it to two pressing problems in AMR. Because
the gut environment is depleted of oxygen (anaerobic), and current technology lacks complete oxygen control,
we will first develop a system for individual control of atmospheric conditions across mini-bioreactors
(atmostat). We will achieve this in the eVOLVER platform, an open-source microbial culture system for
automated control of growth conditions that is easily adapted to new control features, and is exceedingly
scalable. Preliminary results of eVOLVER-atmostat demonstrate unprecedented scale for continuous
culture and evolution of strict anaerobic gut microbes on the benchtop. The first study will determine the
effects of oxygen tension on the mutational fitness landscapes of AMR in E. coli strains. We will implement an
automated antibiotic selection regime in combination with atmostat control of oxygen gradients, and employ
metagenomic sequencing to map the interactions of oxygen, antibiotics, and strains backgrounds in AMR. The
second study will determine how AMR emerges in the ecological context of the gut microbiome, by evolving E.
coli strains with a gut community across multiple antibiotics. Applying state-of-the-art abundance quantification
over time and population genetics approaches, we will define both the eco...

## Key facts

- **NIH application ID:** 10503736
- **Project number:** 1R01AI171100-01
- **Recipient organization:** BOSTON UNIVERSITY (CHARLES RIVER CAMPUS)
- **Principal Investigator:** Ahmad Samir Khalil
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $867,648
- **Award type:** 1
- **Project period:** 2022-06-10 → 2027-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10503736

## Citation

> US National Institutes of Health, RePORTER application 10503736, Programmable benchtop bioreactors for scalable eco-evolutionary dynamics of the human microbiome (1R01AI171100-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10503736. Licensed CC0.

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