title: A Small-Volume, Low-Cost, and Versatile Continuous Culture Device.
abstract: BACKGROUND
  Continuous culture devices can be used for various purposes such as establishing reproducible growth conditions or maintaining cell populations under a constant environment for long periods. However, commercially available instruments are expensive, were not designed to handle small volumes in the milliliter range, and can lack the flexibility required for the diverse experimental needs found in several laboratories.
  
  
  RESULTS
  We developed a versatile continuous culture system and provide detailed instructions as well as a graphical user interface software for potential users to assemble and operate their own instrument. Three culture chambers can be controlled simultaneously with the proposed configuration, and all components are readily available from various sources. We demonstrate that our continuous culture device can be used under different modes, and can easily be programmed to behave either as a turbidostat or chemostat. Addition of fresh medium to the culture vessel can be controlled by a real-time feedback loop or simply calibrated to deliver a defined volume. Furthermore, the selected light-emitting diode and photodetector enable the use of phenol red as a pH indicator, which can be used to indirectly monitor the bulk metabolic activity of a cell population rather than the turbidity.
  
  
  CONCLUSIONS
  This affordable and customizable system will constitute a useful tool in many areas of biology such as microbial ecology as well as systems and synthetic biology.
authors.affiliation: Département de biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Dominick
authors.initials: D
authors.lastname: Matteau
authors.affiliation: Département de biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Vincent
authors.initials: V
authors.lastname: Baby
authors.affiliation: Département de physique, Université de Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Pelletier
authors.affiliation: Département de biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Rodrigue
mesh_terms: D002455:Cell Division / Q000502:physiology*; D045622:Entomoplasmataceae / Q000166:cytology / Q000254:growth & development; D004867:Equipment Design; D004926:Escherichia coli / Q000166:cytology / Q000254:growth & development; D006863:Hydrogen-Ion Concentration; D008828:Microbiological Techniques / Q000191:economics / Q000295:instrumentation* / Q000379:methods*; D008962:Models, Theoretical; D015203:Reproducibility of Results; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000254:growth & development