Summary

In this step by step example, we used BactoBox® to screen 4 candidate growth media for their abilities to support the highest cell concentrations.

Key assumptions and verification tests

To use BactoBox® as a proxy for maximum CFU/mL, we rely on assumptions that have generally been proven valid. But there may be exceptions. You can use our additional workflows to verify these assumptions for your cultures.

The sample is suitable for flow cytometry with predominantly single free-flowing cells

A quick check in a microscope is always a good idea. Also, check Break up clumps and chains for how to get a single-cell suspension.

BactoBox® and plate counts correlates closely in stationary stage.

Run a head-to-head experiment using the Correlation group type to verify correlation between the methods.

Culture has reached stationary stage

Cell concentration is still increasing If the cultures are in exponential or deceleration phase. Run the workflow Track growth curve to verify that the cultures have reached stationary phase.

BactoBox® cell concentration stays relatively constant throughout stationary and decline phase

Run the workflow Track growth curve throughout stationary and decline phase to investigate if this is the case. If the concentration is not constant, Contact our support team.

Next steps

You have now identified which of your growth media that results in highest cell concentrations. We bet you are excited to learn if this is also the growth medium that reaches highest concentrations fastest?

Try a Track growth curve experiment to determine the duration of the lag and growth phases. This will provide valuable insights for selecting the optimal growth medium for your bioprocess.

Note that there may be other factors than growth medium composition that limit a culture from reaching high cell concentrations. For example, if oxygen level (dissolved oxygen) becomes too low the culture may stagnate at suboptimal cell concentrations. Here we use simple shake flasks as a demonstration. You may want to investigate how high max concentrations may be obtained in proper bioreactors where oxygen supply can be controlled more effectively.