I've harvested IPTG induced E.coli BL21DE3 cells' suspension culture by spinning at 5000 rpm/15 min/4 degrees C. The pellet after spin looked pale pink colored. What could be the reasons?
Hi Sai,
I found a similar question asked before
https://www.researchgate.net/post/Can_bacterial_cells_change_their_colour_after_induction
I have also heard that a yeast contamination may alter the colour of your pellet.
Hi there,
What is the protein you are expressing? The color might be due to it.
Once Ifaced this problem and it is because of Pesudomomas contamination.PLz check.
I agree with Nirpendra; Pseudomonas aeruginosa yields a pink pellet. One additional way to "verify" is by the smell. P. aeruginosa cell cultures have a distinct, almost fruity, smell. Some say it's like pineapple, others say it's more like grape. Fruity nonetheless...
Hi,
I yielded pink E. coli when I did a glutardialdehyde crosslinking of E. coli cells in Agarose beads. Do you know if you have significant concentrations of aldehydes in your medium?
Your strain maybe secreting porphyrins in stationary phase growth. If the pellet glows pink under long-wave ultraviolet light, then it is probably coproporphyrin.
All of the above are valid possibilities. The easiest and most straight-forward thing to do would be to just re-do the growth and induction with a new cell culture :)
Use aseptic technique to prevent contamination, but it might just be E. coli expressing your protein, giving specific color. I had observed it when I overexpressed a heme containing protein in E. coli.
I agree with the answers above. The bottom line is check culture purity at every possible stage. It's a minute's work to spread a culture to single colonies on an agar plate. To find out months later that you've been working on the wrong organism is a very painful experience.
Hey Sai, I have similar problems at the moment an just wanted to ask if you figured out what had happend?
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