(592c) Microdroplet Chemostats

We describe an automated microfluidic technology for manipulating and monitoring continuous growth of populations of bacteria in microdroplet chemostats. Classic chemostats facilitate the continuous culture of bacteria, yeast, and algae by replenishing liquids to maintain specific concentrations of cells and growth factors. Chemostats have facilitated a wide-range of studies, including microbial ecology, predator/prey dynamics, and the evolution of drug resistance. However, the consumption of large quantities of reagents and the significant operational challenges of traditional chemostats limit their use. Droplet microfluidics offer a unique solution to creating many parallel chemostats, each of minute volume. Compartmentalizing cells and nutrients in microdroplets of liquid can reduce the complexity and cost of operating many parallel chemostats.  In addition, we characterize the dynamics of bacterial populations in microdroplet chemostats and cellular responses to a range of stable or changing antibiotic concentrations. The method could allow for parallel, long-term studies of microbial ecology, physiology, evolution, and adaptation to chemical environments.