An inexpensive miniature modular turbidostat for characterization and experimental evolution

Chemostats have proven to be extremely valuable in scientific and industrial research.  However, chemostats only allow scientists to probe cells under the condition of nutrient limitation, which represents just a cross section of continuous culture’s full potential.  The turbidostat was conceived to fill this experimental void enabling experiments in nutrient rich conditions very close to the washout point of a chemostat.  Unfortunately, due to commercial unavailability and the technical challenges posed by building a turbidostat, experiments requiring turbidostats and similarly complex devices are rarely performed.  Additionally, continuous culture designs that are more complex than the chemostat can vary wildly due to specific experimental needs, which contributes their limited utility.

We have developed an inexpensive, miniature, multiplexed, modular turbidostat.  Our turbidostat incorporates 3D printable valves and pumps, alongside a modular culture chamber that enables rapid redesign of chambers as need.  So far, derived designs include light induction systems for studying light sensitive inducers and a chamber with built in flourometer.  The control software is written in Python with user programmable modules that enable the user to expand capabilities beyond following a single setpoint, such as dynamically varying cell density and control of multiple media sources.  Ultimately, we aim to create a rich community of users that contribute unique designs to the project, creating a repository of designs to choose from.