4 | CONCLUSIONS
We described here the design and validation of a modular bioreactor module that can be operated under various configurations. Each module can sense and control the pH of its culture medium and can be set to operate in static or dynamic culturing mode to serve specific applications. The modular bioreactor design offers flexibility in terms of culture size, aerobic/anaerobic atmosphere, and static/dynamic culture. Specifically, the bioreactor design enables the creation of simple or complex models of digestive tracts of desired culture sizes. The resulting systems can be used to study the growth and evolution of cultured microbes, such as gut microbes, independent of host immune surveillance as well as to determine the response of the microbial community to controlled availability of specific metabolites that are normally secreted by the host into the digestive tract.