My question concerns the QiagenTM Spin Miniprep kit and the purification of the Low copy pACYC vector from the E.coli DH10b genetic background.

When trying to purify pACYC vectors from the E.coli DH10b genetic background, I have repeatedly noticed that my cell pellet isn't lysed but redissolved after the addition of buffers P2 and P3 to buffer P1. The expected floating cloud of cell debris isn't generated and the lyseblue reagent produces a strawberry yoghurt like color instead of the expected indigo blue color. Surprisingly, this problem only occurs when using the DH10b nature.

Has anyone ever encountered this problem?

Thanks in advance!