Why would clumps occur following the addition of Buffer P2 when using LyseBlue Reagent in a plasmid preparation?
FAQ ID -862

Clumps that occur after addition of Buffer P2 in a bacterial lysate containing LyseBlue reagent indicate poor resuspension of the bacterial cell pellet in Buffer P1. This handling error leads to inefficient cell lysis, and incomplete precipitation of SDS, cell debris, and genomic DNA. When resuspending the cell pellet, vortexing longer or resuspending the pellet by pipetting up and down can help.

If cells have been resuspended properly in P1, “brownish areas” after P2 addition just indicate poor mixing of P1 and P2. To overcome this, continue mixing the solution by inverting it gently until a homogeneous blue suspension is achieved.