Dear community,

First, thank you for the information posted. It has helped before to solve some issues. Now, I want to ask if you have experienced the same issue or have a potential solution for the one below.

In a recent experiment, we grew the same yeast strain expressing GFP reporter construct stably integrated in the genome in 5 bioreactors. We were expecting similar values for all bioreactors. However, in both experiments, one of the bioreactors always displayed much higher values than the others (despite having similar OD values to the others). For us, this makes the data interpretation difficult, since we work with promoter engineering and use GFP/RFP signals to compare promoter strengths (resulting in different expression levels of GFP).

I would like to know if these strong differences in signal detection are common between the bioreactors (despite using the same strain, setup). In addition, we wonder if we can fix the problem (e.g. any type of calibration?).

I have contacted the company assembling the bioreactors and they suggested the following: “Our technical team has pointed out the below points:
– Source of error: Alignment of Laser/spectrometer:
Recommendation: Carefully bend Laser/spectrometer until the value gets better. Proceed to use a nonconductive material for bending, else disassemble the sidewalls of the
reactor (not recommended). >I did this, but it does not help.

Many thanks for any help / comment about this issue.

Sincerely,

Reynel