Long-Term and Programmable Bacterial Subculture in Completely Automated Microchemostats.

A controllable microchemostat can provide an ideal, powerful means to study the growth behavior of microorganisms by improving conventional macroscale chemostat. However, a challenge remains for implementing both continuous growth and active population control of microorganisms at the same time because they keep communicating with nearby culture environments by regulating their metabolism. Here, we present a novel microchemostat that enables reversible bacterial isolation, continuous chemical refreshment, and dynamic physicochemical stimulation. The microchemostat not only controls bacterial growth and subculture conditions in a completely automated and programmed manner but it also makes it possible to manipulate bacterial populations from a single bacterium to an ultrahigh density for long-term subculture periods with ultralow reagent consumption. Moreover, the microchemostat enables in situ measurement and feedback control of bacterial growth and population through various subculture programming modes that are sequentially performed using a single microchemostat over 720 h; to the best of our knowledge, this is the longest microchemostat culture of bacterial cells reported to date. Hence, we ensure that the microchemostat can be further applied to a wide range of microbial studies on a single chip, such as nutrient optimization, genetic induction, environmental selection, high-throughput screening, and evolutionary adaptation.