The omnistat: A flexible continuous-culture system for prolonged experimental evolution

Area of Science:

• Microbial evolution
• Experimental evolution
• Bioreactor design

Background:

• Microbial evolution experiments are crucial for understanding adaptation but require controlled selective forces.
• Continuous cultures offer better control than batch cultures but existing systems are costly or lack versatility.
• There is a need for adaptable and affordable continuous-culture systems for parallel experiments.

Purpose of the Study:

• To present a novel, modular continuous-culture system for microbial evolution.
• To offer a versatile and cost-effective alternative to existing systems.
• To enable precise control over spatiotemporal selective environments.

Main Methods:

• The system utilizes a standard GL45 glass laboratory bottle as a bioreactor.
• A custom head plate allows for dual sensors and multiple input/output ports.
• Modules can be coupled for uni- or bi-directional flow, enabling spatiotemporal variation.

Main Results:

• The system is modular, small (25-250 ml), and adaptable for various running modes (chemostat, auxostat).
• It facilitates parallel experiments and the creation of temporally or spatially variable selection regimes.
• Demonstrated applications include selecting for anticipatory switching and probing epistatic interactions.

Conclusions:

• This flexible culturing platform enhances the investigation of evolutionary and ecological questions.
• It provides precise control over environmental parameters for studying adaptive evolution mechanisms.
• The system aids in understanding evolutionary constraints like phenotypic trade-offs.