> For the complete documentation index, see [llms.txt](https://help.sbtinstruments.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.sbtinstruments.com/mpd/workflows/best-medium/summary.md). # 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.

Assumption	Verification test
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 /spaces/CaBGkox4Fd7NCFFCF47X/pages/EGcffKeYOv3648VI6ANB for how to get a single-cell suspension.
BactoBox® and plate counts correlate closely in stationary phase.	Run a head-to-head experiment using the /spaces/1GbcuPi5f9BbK7GoqDt1/pages/G8wc9pG7mUsiffESyjw1 to verify correlation between the methods.
Culture has reached stationary phase	Cell concentration is still increasing if the cultures are in exponential or deceleration phase. Run the workflow /pages/I0HcPYpXvMRDTZBltrbb to verify that the cultures have reached stationary phase.
BactoBox® cell concentration stays relatively constant throughout stationary and decline phase	Run the workflow /pages/I0HcPYpXvMRDTZBltrbb throughout stationary and decline phase to investigate if this is the case. If the concentration is not constant, /spaces/Qorx08wID6YNpw8pEV0j/pages/l8Gc9LJGCvsSLOjzDNGF.

## 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](/mpd/workflows/track-growth-curve.md) 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. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://help.sbtinstruments.com/mpd/workflows/best-medium/summary.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.