End-of-fermentation cross-check

Run an endpoint BactoBox® vs CFU comparison to check if your bioprocess has further potential.

BactoBox® skill level	Time to complete (E. coli)	Hands-on time	Requirements
🎒 Basic	⏳ 24 hours	⏱️ 2 hours	7.6a v2026.02a

Ever wondered if your fermentation process has more potential? Getting maximal CFU/mL is crucial for vaccines, probiotics, bio-stimulants, and live biotherapeutic products. A simple crosscheck at end-of-fermentation (EoF) may unveil critical insights that unlocks higher CFU/mL.

Cross-check BactoBox® and plate count results

The importance of harvest time is illustrated in the below P. fluorescens example.

• In the cyan window, the cell concentration is practically identical to the concentration of culturable (cells ~ CFU). Harvesting later could potentially increase the CFU/mL of the final product.

• In the grey window the cell concentration is significantly higher than the proportion of culturable cells (cells > CFU). Harvesting earlier could potentially increase the CFU/mL of the final product.

P. fluorescens growth curve tracked with BactoBox® (lavender) and plate counts (yellow). Cyan box highlights where cells and CFUs are within 50%. Grey box highlights region where cell concentration is significantly higher than CFUs. All measurements were done by three individual dilution series prior to measurements. Error bars reflect standard deviation.

Overview

In this step by step guide we will demonstrate how to crosscheck BactoBox® and CFU results. You will need a fresh EoF culture sample. This should preferably be from a bioreactor, but you can also simulate the process with a simple shake flask culture of E. coli.

The overall steps in the workflow are given below.

1. Get things ready

2. Create measurement group

3. Retrieve culture sample

4. BactoBox measurements

5. Calculate dilutions

6. Plate dilutions

7. Count colonies

8. Cross-check data

9. Summary

Summary

With this introduction you are now ready to check if your bioprocess has higher potential. Next step is Get things ready.