DNA pellet may be sticky and stubborn to dissolve, if PK treatment were insufficient. To avoid this, start from a smaller piece of tissue with more PK with prolonged treatment. Alternatively, add 1 or 2x volumn of TNESU8 buffer to the undisolved DNA pellet in TE, incubate for a few days at room temperature to swell it. The swelled and dissolved DNA pellet can be proceeded to the 2nd round Phe-Chl step.